diff --git a/lib/private/Files/ObjectStore/ObjectStoreStorage.php b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
index 26823f65c2f0e..7b731a4d40d82 100644
--- a/lib/private/Files/ObjectStore/ObjectStoreStorage.php
+++ b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
@@ -17,6 +17,7 @@
 use OC\Files\Storage\PolyFill\CopyDirectory;
 use OCP\Files\Cache\ICache;
 use OCP\Files\Cache\ICacheEntry;
+use OCP\Files\Cache\IScanner;
 use OCP\Files\FileInfo;
 use OCP\Files\GenericFileException;
 use OCP\Files\NotFoundException;
@@ -64,7 +65,7 @@ public function __construct($params) {
 		$this->logger = \OCP\Server::get(LoggerInterface::class);
 	}
 
-	public function mkdir($path, bool $force = false) {
+	public function mkdir($path, bool $force = false): bool {
 		$path = $this->normalizePath($path);
 		if (!$force && $this->file_exists($path)) {
 			$this->logger->warning("Tried to create an object store folder that already exists: $path");
@@ -130,7 +131,7 @@ private function normalizePath($path) {
 	 * Object Stores use a NoopScanner because metadata is directly stored in
 	 * the file cache and cannot really scan the filesystem. The storage passed in is not used anywhere.
 	 */
-	public function getScanner($path = '', $storage = null) {
+	public function getScanner($path = '', $storage = null): IScanner {
 		if (!$storage) {
 			$storage = $this;
 		}
@@ -141,11 +142,11 @@ public function getScanner($path = '', $storage = null) {
 		return $this->scanner;
 	}
 
-	public function getId() {
+	public function getId(): string {
 		return $this->id;
 	}
 
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		$path = $this->normalizePath($path);
 		$entry = $this->getCache()->get($path);
 
@@ -175,7 +176,7 @@ private function rmObjects(ICacheEntry $entry): bool {
 		return true;
 	}
 
-	public function unlink($path) {
+	public function unlink($path): bool {
 		$path = $this->normalizePath($path);
 		$entry = $this->getCache()->get($path);
 
@@ -209,7 +210,7 @@ public function rmObject(ICacheEntry $entry): bool {
 		return true;
 	}
 
-	public function stat($path) {
+	public function stat($path): array|false {
 		$path = $this->normalizePath($path);
 		$cacheEntry = $this->getCache()->get($path);
 		if ($cacheEntry instanceof CacheEntry) {
@@ -226,7 +227,7 @@ public function stat($path) {
 		}
 	}
 
-	public function getPermissions($path) {
+	public function getPermissions($path): int {
 		$stat = $this->stat($path);
 
 		if (is_array($stat) && isset($stat['permissions'])) {
@@ -268,7 +269,7 @@ public function opendir($path) {
 		}
 	}
 
-	public function filetype($path) {
+	public function filetype($path): string|false {
 		$path = $this->normalizePath($path);
 		$stat = $this->stat($path);
 		if ($stat) {
@@ -373,12 +374,12 @@ public function fopen($path, $mode) {
 		return false;
 	}
 
-	public function file_exists($path) {
+	public function file_exists($path): bool {
 		$path = $this->normalizePath($path);
 		return (bool)$this->stat($path);
 	}
 
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		$source = $this->normalizePath($source);
 		$target = $this->normalizePath($target);
 		$this->remove($target);
@@ -387,12 +388,12 @@ public function rename($source, $target) {
 		return true;
 	}
 
-	public function getMimeType($path) {
+	public function getMimeType($path): string|false {
 		$path = $this->normalizePath($path);
 		return parent::getMimeType($path);
 	}
 
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		if (is_null($mtime)) {
 			$mtime = time();
 		}
@@ -443,22 +444,15 @@ public function writeBack($tmpFile, $path) {
 		$this->writeStream($path, fopen($tmpFile, 'r'), $size);
 	}
 
-	/**
-	 * external changes are not supported, exclusive access to the object storage is assumed
-	 *
-	 * @param string $path
-	 * @param int $time
-	 * @return false
-	 */
-	public function hasUpdated($path, $time) {
+	public function hasUpdated($path, $time): bool {
 		return false;
 	}
 
-	public function needsPartFile() {
+	public function needsPartFile(): bool {
 		return false;
 	}
 
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): int {
 		$fh = fopen('php://temp', 'w+');
 		fwrite($fh, $data);
 		rewind($fh);
@@ -571,7 +565,7 @@ public function copyFromStorage(
 		$sourceInternalPath,
 		$targetInternalPath,
 		$preserveMtime = false,
-	) {
+	): bool {
 		if ($sourceStorage->instanceOfStorage(ObjectStoreStorage::class)) {
 			/** @var ObjectStoreStorage $sourceStorage */
 			if ($sourceStorage->getObjectStore()->getStorageId() === $this->getObjectStore()->getStorageId()) {
@@ -627,7 +621,7 @@ public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 		return true;
 	}
 
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		$source = $this->normalizePath($source);
 		$target = $this->normalizePath($target);
 
@@ -695,7 +689,6 @@ public function startChunkedWrite(string $targetPath): string {
 	}
 
 	/**
-	 *
 	 * @throws GenericFileException
 	 */
 	public function putChunkedWritePart(
diff --git a/lib/private/Files/Storage/Common.php b/lib/private/Files/Storage/Common.php
index b6f14321f6141..375e0987e2580 100644
--- a/lib/private/Files/Storage/Common.php
+++ b/lib/private/Files/Storage/Common.php
@@ -17,6 +17,11 @@
 use OC\Files\Filesystem;
 use OC\Files\Storage\Wrapper\Jail;
 use OC\Files\Storage\Wrapper\Wrapper;
+use OCP\Files\Cache\ICache;
+use OCP\Files\Cache\IPropagator;
+use OCP\Files\Cache\IScanner;
+use OCP\Files\Cache\IUpdater;
+use OCP\Files\Cache\IWatcher;
 use OCP\Files\ForbiddenException;
 use OCP\Files\GenericFileException;
 use OCP\Files\IFilenameValidator;
@@ -65,9 +70,8 @@ public function __construct($parameters) {
 	 * Remove a file or folder
 	 *
 	 * @param string $path
-	 * @return bool
 	 */
-	protected function remove($path) {
+	protected function remove($path): bool {
 		if ($this->is_dir($path)) {
 			return $this->rmdir($path);
 		} elseif ($this->is_file($path)) {
@@ -77,11 +81,11 @@ protected function remove($path) {
 		}
 	}
 
-	public function is_dir($path) {
+	public function is_dir($path): bool {
 		return $this->filetype($path) === 'dir';
 	}
 
-	public function is_file($path) {
+	public function is_file($path): bool {
 		return $this->filetype($path) === 'file';
 	}
 
@@ -98,27 +102,27 @@ public function filesize($path): false|int|float {
 		}
 	}
 
-	public function isReadable($path) {
+	public function isReadable($path): bool {
 		// at least check whether it exists
 		// subclasses might want to implement this more thoroughly
 		return $this->file_exists($path);
 	}
 
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		// at least check whether it exists
 		// subclasses might want to implement this more thoroughly
 		// a non-existing file/folder isn't updatable
 		return $this->file_exists($path);
 	}
 
-	public function isCreatable($path) {
+	public function isCreatable($path): bool {
 		if ($this->is_dir($path) && $this->isUpdatable($path)) {
 			return true;
 		}
 		return false;
 	}
 
-	public function isDeletable($path) {
+	public function isDeletable($path): bool {
 		if ($path === '' || $path === '/') {
 			return $this->isUpdatable($path);
 		}
@@ -126,11 +130,11 @@ public function isDeletable($path) {
 		return $this->isUpdatable($parent) && $this->isUpdatable($path);
 	}
 
-	public function isSharable($path) {
+	public function isSharable($path): bool {
 		return $this->isReadable($path);
 	}
 
-	public function getPermissions($path) {
+	public function getPermissions($path): int {
 		$permissions = 0;
 		if ($this->isCreatable($path)) {
 			$permissions |= \OCP\Constants::PERMISSION_CREATE;
@@ -150,7 +154,7 @@ public function getPermissions($path) {
 		return $permissions;
 	}
 
-	public function filemtime($path) {
+	public function filemtime($path): int|false {
 		$stat = $this->stat($path);
 		if (isset($stat['mtime']) && $stat['mtime'] > 0) {
 			return $stat['mtime'];
@@ -159,7 +163,7 @@ public function filemtime($path) {
 		}
 	}
 
-	public function file_get_contents($path) {
+	public function file_get_contents($path): bool|string {
 		$handle = $this->fopen($path, 'r');
 		if (!$handle) {
 			return false;
@@ -169,7 +173,7 @@ public function file_get_contents($path) {
 		return $data;
 	}
 
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): float|bool|int {
 		$handle = $this->fopen($path, 'w');
 		if (!$handle) {
 			return false;
@@ -180,14 +184,14 @@ public function file_put_contents($path, $data) {
 		return $count;
 	}
 
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		$this->remove($target);
 
 		$this->removeCachedFile($source);
 		return $this->copy($source, $target) and $this->remove($source);
 	}
 
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		if ($this->is_dir($source)) {
 			$this->remove($target);
 			$dir = $this->opendir($source);
@@ -214,7 +218,7 @@ public function copy($source, $target) {
 		}
 	}
 
-	public function getMimeType($path) {
+	public function getMimeType($path): bool|string {
 		if ($this->is_dir($path)) {
 			return 'httpd/unix-directory';
 		} elseif ($this->file_exists($path)) {
@@ -224,7 +228,7 @@ public function getMimeType($path) {
 		}
 	}
 
-	public function hash($type, $path, $raw = false) {
+	public function hash($type, $path, $raw = false): bool|string {
 		$fh = $this->fopen($path, 'rb');
 		$ctx = hash_init($type);
 		hash_update_stream($ctx, $fh);
@@ -232,15 +236,11 @@ public function hash($type, $path, $raw = false) {
 		return hash_final($ctx, $raw);
 	}
 
-	public function getLocalFile($path) {
+	public function getLocalFile($path): bool|string {
 		return $this->getCachedFile($path);
 	}
 
-	/**
-	 * @param string $path
-	 * @param string $target
-	 */
-	private function addLocalFolder($path, $target) {
+	private function addLocalFolder($path, $target): void {
 		$dh = $this->opendir($path);
 		if (is_resource($dh)) {
 			while (($file = readdir($dh)) !== false) {
@@ -257,12 +257,7 @@ private function addLocalFolder($path, $target) {
 		}
 	}
 
-	/**
-	 * @param string $query
-	 * @param string $dir
-	 * @return array
-	 */
-	protected function searchInDir($query, $dir = '') {
+	protected function searchInDir($query, $dir = ''): array {
 		$files = [];
 		$dh = $this->opendir($dir);
 		if (is_resource($dh)) {
@@ -283,18 +278,15 @@ protected function searchInDir($query, $dir = '') {
 	}
 
 	/**
+	 * @inheritDoc
 	 * Check if a file or folder has been updated since $time
 	 *
 	 * The method is only used to check if the cache needs to be updated. Storage backends that don't support checking
 	 * the mtime should always return false here. As a result storage implementations that always return false expect
 	 * exclusive access to the backend and will not pick up files that have been added in a way that circumvents
 	 * Nextcloud filesystem.
-	 *
-	 * @param string $path
-	 * @param int $time
-	 * @return bool
 	 */
-	public function hasUpdated($path, $time) {
+	public function hasUpdated($path, $time): bool {
 		return $this->filemtime($path) > $time;
 	}
 
@@ -306,23 +298,18 @@ protected function getCacheDependencies(): CacheDependencies {
 		return $dependencies;
 	}
 
-	/**
-	 * @return Cache
-	 */
-	public function getCache($path = '', $storage = null) {
+	public function getCache($path = '', $storage = null): ICache {
 		if (!$storage) {
 			$storage = $this;
 		}
-		/** @psalm-suppress NoInterfaceProperties The isset check is safe */
+		/** @var self $storage */
 		if (!isset($storage->cache)) {
 			$storage->cache = new Cache($storage, $this->getCacheDependencies());
 		}
-		/** @psalm-suppress NullableReturnStatement False-positive, as the if above avoids this being null */
-		/** @psalm-suppress NoInterfaceProperties Legacy */
 		return $storage->cache;
 	}
 
-	public function getScanner($path = '', $storage = null) {
+	public function getScanner($path = '', $storage = null): IScanner {
 		if (!$storage) {
 			$storage = $this;
 		}
@@ -335,7 +322,7 @@ public function getScanner($path = '', $storage = null) {
 		return $storage->scanner;
 	}
 
-	public function getWatcher($path = '', $storage = null) {
+	public function getWatcher($path = '', $storage = null): IWatcher {
 		if (!$storage) {
 			$storage = $this;
 		}
@@ -347,7 +334,7 @@ public function getWatcher($path = '', $storage = null) {
 		return $this->watcher;
 	}
 
-	public function getPropagator($storage = null) {
+	public function getPropagator($storage = null): IPropagator {
 		if (!$storage) {
 			$storage = $this;
 		}
@@ -362,27 +349,24 @@ public function getPropagator($storage = null) {
 		return $storage->propagator;
 	}
 
-	/**
-	 * get a propagator instance for the cache
-	 *
-	 * @param \OC\Files\Storage\Storage $storage (optional) the storage to pass to the watcher
-	 * @return Updater
-	 */
-	public function getUpdater($storage = null) {
+	public function getUpdater($storage = null): IUpdater {
 		if (!$storage) {
 			$storage = $this;
 		}
 		if (!$storage->instanceOfStorage(self::class)) {
 			throw new \InvalidArgumentException('Storage is not of the correct class');
 		}
+		/** @var self $storage */
 		if (!isset($storage->updater)) {
 			$storage->updater = new Updater($storage);
 		}
 		return $storage->updater;
 	}
 
-	public function getStorageCache($storage = null) {
-		return $this->getCache($storage)->getStorageCache();
+	public function getStorageCache($storage = null): \OC\Files\Cache\Storage {
+		/** @var Cache $cache */
+		$cache = $this->getCache($storage);
+		return $cache->getStorageCache();
 	}
 
 	public function getOwner($path): string|false {
@@ -399,7 +383,7 @@ public function getOwner($path): string|false {
 	 * @param string $path
 	 * @return string|false
 	 */
-	public function getETag($path) {
+	public function getETag($path): bool|string {
 		return uniqid();
 	}
 
@@ -410,7 +394,7 @@ public function getETag($path) {
 	 * @param string $path The path to clean
 	 * @return string cleaned path
 	 */
-	public function cleanPath($path) {
+	public function cleanPath($path): string {
 		if (strlen($path) == 0 or $path[0] != '/') {
 			$path = '/' . $path;
 		}
@@ -432,7 +416,7 @@ public function cleanPath($path) {
 	 *
 	 * @return bool
 	 */
-	public function test() {
+	public function test(): bool {
 		try {
 			if ($this->stat('')) {
 				return true;
@@ -454,14 +438,14 @@ public function test() {
 	 * @param string $path
 	 * @return int|float|false
 	 */
-	public function free_space($path) {
+	public function free_space($path): float|bool|int {
 		return \OCP\Files\FileInfo::SPACE_UNKNOWN;
 	}
 
 	/**
 	 * {@inheritdoc}
 	 */
-	public function isLocal() {
+	public function isLocal(): bool {
 		// the common implementation returns a temporary file by
 		// default, which is not local
 		return false;
@@ -473,7 +457,7 @@ public function isLocal() {
 	 * @param string $class
 	 * @return bool
 	 */
-	public function instanceOfStorage($class) {
+	public function instanceOfStorage($class): bool {
 		if (ltrim($class, '\\') === 'OC\Files\Storage\Shared') {
 			// FIXME Temporary fix to keep existing checks working
 			$class = '\OCA\Files_Sharing\SharedStorage';
@@ -489,7 +473,7 @@ public function instanceOfStorage($class) {
 	 * @param string $path
 	 * @return array|false
 	 */
-	public function getDirectDownload($path) {
+	public function getDirectDownload($path): bool|array {
 		return [];
 	}
 
@@ -497,7 +481,7 @@ public function getDirectDownload($path) {
 	 * @inheritdoc
 	 * @throws InvalidPathException
 	 */
-	public function verifyPath($path, $fileName) {
+	public function verifyPath($path, $fileName): void {
 		$this->getFilenameValidator()
 			->validateFilename($fileName);
 
@@ -529,7 +513,7 @@ protected function getFilenameValidator(): IFilenameValidator {
 	/**
 	 * @param array $options
 	 */
-	public function setMountOptions(array $options) {
+	public function setMountOptions(array $options): void {
 		$this->mountOptions = $options;
 	}
 
@@ -538,7 +522,7 @@ public function setMountOptions(array $options) {
 	 * @param mixed $default
 	 * @return mixed
 	 */
-	public function getMountOption($name, $default = null) {
+	public function getMountOption($name, $default = null): mixed {
 		return $this->mountOptions[$name] ?? $default;
 	}
 
@@ -549,7 +533,7 @@ public function getMountOption($name, $default = null) {
 	 * @param bool $preserveMtime
 	 * @return bool
 	 */
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = false) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = false): bool {
 		if ($sourceStorage === $this) {
 			return $this->copy($sourceInternalPath, $targetInternalPath);
 		}
@@ -615,7 +599,7 @@ private function isSameStorage(IStorage $storage): bool {
 	 * @param string $targetInternalPath
 	 * @return bool
 	 */
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if ($this->isSameStorage($sourceStorage)) {
 			// resolve any jailed paths
 			while ($sourceStorage->instanceOfStorage(Jail::class)) {
@@ -644,7 +628,7 @@ public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 		return $result;
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		if (Filesystem::isFileBlacklisted($path)) {
 			throw new ForbiddenException('Invalid path: ' . $path, false);
 		}
@@ -674,7 +658,7 @@ public function getMetaData($path) {
 		return $data;
 	}
 
-	public function acquireLock($path, $type, ILockingProvider $provider) {
+	public function acquireLock($path, $type, ILockingProvider $provider): void {
 		$logger = $this->getLockLogger();
 		if ($logger) {
 			$typeString = ($type === ILockingProvider::LOCK_SHARED) ? 'shared' : 'exclusive';
@@ -701,7 +685,7 @@ public function acquireLock($path, $type, ILockingProvider $provider) {
 		}
 	}
 
-	public function releaseLock($path, $type, ILockingProvider $provider) {
+	public function releaseLock($path, $type, ILockingProvider $provider): void {
 		$logger = $this->getLockLogger();
 		if ($logger) {
 			$typeString = ($type === ILockingProvider::LOCK_SHARED) ? 'shared' : 'exclusive';
@@ -728,7 +712,7 @@ public function releaseLock($path, $type, ILockingProvider $provider) {
 		}
 	}
 
-	public function changeLock($path, $type, ILockingProvider $provider) {
+	public function changeLock($path, $type, ILockingProvider $provider): void {
 		$logger = $this->getLockLogger();
 		if ($logger) {
 			$typeString = ($type === ILockingProvider::LOCK_SHARED) ? 'shared' : 'exclusive';
@@ -766,14 +750,14 @@ private function getLockLogger(): ?LoggerInterface {
 	/**
 	 * @return array [ available, last_checked ]
 	 */
-	public function getAvailability() {
+	public function getAvailability(): array {
 		return $this->getStorageCache()->getAvailability();
 	}
 
 	/**
 	 * @param bool $isAvailable
 	 */
-	public function setAvailability($isAvailable) {
+	public function setAvailability($isAvailable): void {
 		$this->getStorageCache()->setAvailability($isAvailable);
 	}
 
@@ -793,7 +777,7 @@ public function setOwner(?string $user): void {
 	/**
 	 * @return bool
 	 */
-	public function needsPartFile() {
+	public function needsPartFile(): bool {
 		return true;
 	}
 
diff --git a/lib/private/Files/Storage/CommonTest.php b/lib/private/Files/Storage/CommonTest.php
index efdd36345785c..f49666648c2d2 100644
--- a/lib/private/Files/Storage/CommonTest.php
+++ b/lib/private/Files/Storage/CommonTest.php
@@ -18,43 +18,43 @@ public function __construct($params) {
 		$this->storage = new \OC\Files\Storage\Local($params);
 	}
 
-	public function getId() {
+	public function getId(): string {
 		return 'test::' . $this->storage->getId();
 	}
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		return $this->storage->mkdir($path);
 	}
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		return $this->storage->rmdir($path);
 	}
 	public function opendir($path) {
 		return $this->storage->opendir($path);
 	}
-	public function stat($path) {
+	public function stat($path): bool|array {
 		return $this->storage->stat($path);
 	}
-	public function filetype($path) {
+	public function filetype($path): bool|string {
 		return @$this->storage->filetype($path);
 	}
-	public function isReadable($path) {
+	public function isReadable($path): bool {
 		return $this->storage->isReadable($path);
 	}
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		return $this->storage->isUpdatable($path);
 	}
-	public function file_exists($path) {
+	public function file_exists($path): bool {
 		return $this->storage->file_exists($path);
 	}
-	public function unlink($path) {
+	public function unlink($path): bool {
 		return $this->storage->unlink($path);
 	}
 	public function fopen($path, $mode) {
 		return $this->storage->fopen($path, $mode);
 	}
-	public function free_space($path) {
+	public function free_space($path): float|bool|int {
 		return $this->storage->free_space($path);
 	}
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		return $this->storage->touch($path, $mtime);
 	}
 }
diff --git a/lib/private/Files/Storage/DAV.php b/lib/private/Files/Storage/DAV.php
index 87aa78887b507..6164a492b09e1 100644
--- a/lib/private/Files/Storage/DAV.php
+++ b/lib/private/Files/Storage/DAV.php
@@ -128,7 +128,7 @@ public function __construct($params) {
 		$this->mimeTypeDetector = \OC::$server->getMimeTypeDetector();
 	}
 
-	protected function init() {
+	protected function init(): void {
 		if ($this->ready) {
 			return;
 		}
@@ -177,17 +177,15 @@ protected function init() {
 	/**
 	 * Clear the stat cache
 	 */
-	public function clearStatCache() {
+	public function clearStatCache(): void {
 		$this->statCache->clear();
 	}
 
-	/** {@inheritdoc} */
-	public function getId() {
+	public function getId(): string {
 		return 'webdav::' . $this->user . '@' . $this->host . '/' . $this->root;
 	}
 
-	/** {@inheritdoc} */
-	public function createBaseUri() {
+	public function createBaseUri(): string {
 		$baseUri = 'http';
 		if ($this->secure) {
 			$baseUri .= 's';
@@ -196,8 +194,7 @@ public function createBaseUri() {
 		return $baseUri;
 	}
 
-	/** {@inheritdoc} */
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		$this->init();
 		$path = $this->cleanPath($path);
 		$result = $this->simpleResponse('MKCOL', $path, null, 201);
@@ -207,8 +204,7 @@ public function mkdir($path) {
 		return $result;
 	}
 
-	/** {@inheritdoc} */
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		$this->init();
 		$path = $this->cleanPath($path);
 		// FIXME: some WebDAV impl return 403 when trying to DELETE
@@ -219,7 +215,6 @@ public function rmdir($path) {
 		return $result;
 	}
 
-	/** {@inheritdoc} */
 	public function opendir($path) {
 		$this->init();
 		$path = $this->cleanPath($path);
@@ -248,7 +243,7 @@ public function opendir($path) {
 	 *
 	 * @throws ClientHttpException
 	 */
-	protected function propfind($path) {
+	protected function propfind($path): bool|array {
 		$path = $this->cleanPath($path);
 		$cachedResponse = $this->statCache->get($path);
 		// we either don't know it, or we know it exists but need more details
@@ -276,8 +271,7 @@ protected function propfind($path) {
 		return $response;
 	}
 
-	/** {@inheritdoc} */
-	public function filetype($path) {
+	public function filetype($path): bool|string {
 		try {
 			$response = $this->propfind($path);
 			if ($response === false) {
@@ -295,8 +289,7 @@ public function filetype($path) {
 		return false;
 	}
 
-	/** {@inheritdoc} */
-	public function file_exists($path) {
+	public function file_exists($path): bool {
 		try {
 			$path = $this->cleanPath($path);
 			$cachedState = $this->statCache->get($path);
@@ -314,8 +307,7 @@ public function file_exists($path) {
 		return false;
 	}
 
-	/** {@inheritdoc} */
-	public function unlink($path) {
+	public function unlink($path): bool {
 		$this->init();
 		$path = $this->cleanPath($path);
 		$result = $this->simpleResponse('DELETE', $path, null, 204);
@@ -324,7 +316,6 @@ public function unlink($path) {
 		return $result;
 	}
 
-	/** {@inheritdoc} */
 	public function fopen($path, $mode) {
 		$this->init();
 		$path = $this->cleanPath($path);
@@ -402,13 +393,12 @@ public function fopen($path, $mode) {
 	/**
 	 * @param string $tmpFile
 	 */
-	public function writeBack($tmpFile, $path) {
+	public function writeBack($tmpFile, $path): void {
 		$this->uploadFile($tmpFile, $path);
 		unlink($tmpFile);
 	}
 
-	/** {@inheritdoc} */
-	public function free_space($path) {
+	public function free_space($path): float|bool|int {
 		$this->init();
 		$path = $this->cleanPath($path);
 		try {
@@ -426,8 +416,7 @@ public function free_space($path) {
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		$this->init();
 		if (is_null($mtime)) {
 			$mtime = time();
@@ -469,7 +458,7 @@ public function touch($path, $mtime = null) {
 	 * @param mixed $data
 	 * @return int|float|false
 	 */
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): float|bool|int {
 		$path = $this->cleanPath($path);
 		$result = parent::file_put_contents($path, $data);
 		$this->statCache->remove($path);
@@ -480,7 +469,7 @@ public function file_put_contents($path, $data) {
 	 * @param string $path
 	 * @param string $target
 	 */
-	protected function uploadFile($path, $target) {
+	protected function uploadFile($path, $target): void {
 		$this->init();
 
 		// invalidate
@@ -500,8 +489,7 @@ protected function uploadFile($path, $target) {
 		$this->removeCachedFile($target);
 	}
 
-	/** {@inheritdoc} */
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		$this->init();
 		$source = $this->cleanPath($source);
 		$target = $this->cleanPath($target);
@@ -532,8 +520,7 @@ public function rename($source, $target) {
 		return false;
 	}
 
-	/** {@inheritdoc} */
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		$this->init();
 		$source = $this->cleanPath($source);
 		$target = $this->cleanPath($target);
@@ -561,7 +548,7 @@ public function copy($source, $target) {
 		return false;
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		if (Filesystem::isFileBlacklisted($path)) {
 			throw new ForbiddenException('Invalid path: ' . $path, false);
 		}
@@ -623,15 +610,13 @@ private function getMetaFromPropfind(string $path, array $response): array {
 		];
 	}
 
-	/** {@inheritdoc} */
-	public function stat($path) {
+	public function stat($path): array|false {
 		$meta = $this->getMetaData($path);
 		return $meta ?: false;
 
 	}
 
-	/** {@inheritdoc} */
-	public function getMimeType($path) {
+	public function getMimeType($path): bool|string {
 		$meta = $this->getMetaData($path);
 		return $meta ? $meta['mimetype'] : false;
 	}
@@ -640,7 +625,7 @@ public function getMimeType($path) {
 	 * @param string $path
 	 * @return string
 	 */
-	public function cleanPath($path) {
+	public function cleanPath($path): string {
 		if ($path === '') {
 			return $path;
 		}
@@ -655,7 +640,7 @@ public function cleanPath($path) {
 	 * @param string $path to encode
 	 * @return string encoded path
 	 */
-	protected function encodePath($path) {
+	protected function encodePath($path): string {
 		// slashes need to stay
 		return str_replace('%2F', '/', rawurlencode($path));
 	}
@@ -669,7 +654,7 @@ protected function encodePath($path) {
 	 * @throws StorageInvalidException
 	 * @throws StorageNotAvailableException
 	 */
-	protected function simpleResponse($method, $path, $body, $expected) {
+	protected function simpleResponse($method, $path, $body, $expected): bool {
 		$path = $this->cleanPath($path);
 		try {
 			$response = $this->client->request($method, $this->encodePath($path), $body);
@@ -691,46 +676,37 @@ protected function simpleResponse($method, $path, $body, $expected) {
 	/**
 	 * check if curl is installed
 	 */
-	public static function checkDependencies() {
+	public static function checkDependencies(): bool {
 		return true;
 	}
 
-	/** {@inheritdoc} */
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		return (bool)($this->getPermissions($path) & Constants::PERMISSION_UPDATE);
 	}
 
-	/** {@inheritdoc} */
-	public function isCreatable($path) {
+	public function isCreatable($path): bool {
 		return (bool)($this->getPermissions($path) & Constants::PERMISSION_CREATE);
 	}
 
-	/** {@inheritdoc} */
-	public function isSharable($path) {
+	public function isSharable($path): bool {
 		return (bool)($this->getPermissions($path) & Constants::PERMISSION_SHARE);
 	}
 
-	/** {@inheritdoc} */
-	public function isDeletable($path) {
+	public function isDeletable($path): bool {
 		return (bool)($this->getPermissions($path) & Constants::PERMISSION_DELETE);
 	}
 
-	/** {@inheritdoc} */
-	public function getPermissions($path) {
+	public function getPermissions($path): int {
 		$stat = $this->getMetaData($path);
 		return $stat ? $stat['permissions'] : 0;
 	}
 
-	public function getETag($path) {
+	public function getETag($path): bool|string {
 		$meta = $this->getMetaData($path);
 		return $meta ? $meta['etag'] : false;
 	}
 
-	/**
-	 * @param string $permissionsString
-	 * @return int
-	 */
-	protected function parsePermissions($permissionsString) {
+	protected function parsePermissions($permissionsString): int {
 		$permissions = Constants::PERMISSION_READ;
 		if (str_contains($permissionsString, 'R')) {
 			$permissions |= Constants::PERMISSION_SHARE;
@@ -748,15 +724,7 @@ protected function parsePermissions($permissionsString) {
 		return $permissions;
 	}
 
-	/**
-	 * check if a file or folder has been updated since $time
-	 *
-	 * @param string $path
-	 * @param int $time
-	 * @throws \OCP\Files\StorageNotAvailableException
-	 * @return bool
-	 */
-	public function hasUpdated($path, $time) {
+	public function hasUpdated($path, $time): bool {
 		$this->init();
 		$path = $this->cleanPath($path);
 		try {
@@ -822,7 +790,7 @@ public function hasUpdated($path, $time) {
 	 *                                      which might be temporary
 	 * @throws ForbiddenException if the action is not allowed
 	 */
-	protected function convertException(Exception $e, $path = '') {
+	protected function convertException(Exception $e, $path = ''): void {
 		Server::get(LoggerInterface::class)->debug($e->getMessage(), ['app' => 'files_external', 'exception' => $e]);
 		if ($e instanceof ClientHttpException) {
 			if ($e->getHttpStatus() === Http::STATUS_LOCKED) {
diff --git a/lib/private/Files/Storage/FailedStorage.php b/lib/private/Files/Storage/FailedStorage.php
index 87a6e7f5041e7..35c78bd326904 100644
--- a/lib/private/Files/Storage/FailedStorage.php
+++ b/lib/private/Files/Storage/FailedStorage.php
@@ -29,168 +29,163 @@ public function __construct($params) {
 		}
 	}
 
-	public function getId() {
+	public function getId(): string {
 		// we can't return anything sane here
 		return 'failedstorage';
 	}
 
-	public function mkdir($path) {
+	public function mkdir($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function rmdir($path) {
+	public function rmdir($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function opendir($path) {
+	public function opendir($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function is_dir($path) {
+	public function is_dir($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function is_file($path) {
+	public function is_file($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function stat($path) {
+	public function stat($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function filetype($path) {
+	public function filetype($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function filesize($path): false|int|float {
+	public function filesize($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function isCreatable($path) {
+	public function isCreatable($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function isReadable($path) {
+	public function isReadable($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function isUpdatable($path) {
+	public function isUpdatable($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function isDeletable($path) {
+	public function isDeletable($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function isSharable($path) {
+	public function isSharable($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function getPermissions($path) {
+	public function getPermissions($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function file_exists($path) {
+	public function file_exists($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function filemtime($path) {
+	public function filemtime($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function file_get_contents($path) {
+	public function file_get_contents($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function unlink($path) {
+	public function unlink($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function rename($source, $target) {
+	public function rename($source, $target): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function copy($source, $target) {
+	public function copy($source, $target): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function fopen($path, $mode) {
+	public function fopen($path, $mode): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function getMimeType($path) {
+	public function getMimeType($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function hash($type, $path, $raw = false) {
+	public function hash($type, $path, $raw = false): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function free_space($path) {
+	public function free_space($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function search($query) {
+	public function touch($path, $mtime = null): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function touch($path, $mtime = null) {
+	public function getLocalFile($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function getLocalFile($path) {
+	public function hasUpdated($path, $time): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function hasUpdated($path, $time) {
+	public function getETag($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function getETag($path) {
+	public function getDirectDownload($path): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function getDirectDownload($path) {
-		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
-	}
-
-	public function verifyPath($path, $fileName) {
-		return true;
+	public function verifyPath($path, $fileName): void {
 	}
 
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = false) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = false): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function acquireLock($path, $type, ILockingProvider $provider) {
+	public function acquireLock($path, $type, ILockingProvider $provider): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function releaseLock($path, $type, ILockingProvider $provider) {
+	public function releaseLock($path, $type, ILockingProvider $provider): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function changeLock($path, $type, ILockingProvider $provider) {
+	public function changeLock($path, $type, ILockingProvider $provider): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function getAvailability() {
+	public function getAvailability(): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function setAvailability($isAvailable) {
+	public function setAvailability($isAvailable): never {
 		throw new StorageNotAvailableException($this->e->getMessage(), $this->e->getCode(), $this->e);
 	}
 
-	public function getCache($path = '', $storage = null) {
+	public function getCache($path = '', $storage = null): FailedCache {
 		return new FailedCache();
 	}
 }
diff --git a/lib/private/Files/Storage/Home.php b/lib/private/Files/Storage/Home.php
index fd1d287629fc2..6729b293860ab 100644
--- a/lib/private/Files/Storage/Home.php
+++ b/lib/private/Files/Storage/Home.php
@@ -8,6 +8,8 @@
 namespace OC\Files\Storage;
 
 use OC\Files\Cache\HomePropagator;
+use OCP\Files\Cache\ICache;
+use OCP\Files\Cache\IPropagator;
 use OCP\IUser;
 
 /**
@@ -38,41 +40,31 @@ public function __construct($arguments) {
 		parent::__construct(['datadir' => $datadir]);
 	}
 
-	public function getId() {
+	public function getId(): string {
 		return $this->id;
 	}
 
-	/**
-	 * @return \OC\Files\Cache\HomeCache
-	 */
-	public function getCache($path = '', $storage = null) {
+	public function getCache($path = '', $storage = null): ICache {
 		if (!$storage) {
 			$storage = $this;
 		}
 		if (!isset($this->cache)) {
 			$this->cache = new \OC\Files\Cache\HomeCache($storage, $this->getCacheDependencies());
 		}
-		/** @var \OC\Files\Cache\HomeCache */
 		return $this->cache;
 	}
 
-	public function getPropagator($storage = null) {
+	public function getPropagator($storage = null): IPropagator {
 		if (!$storage) {
 			$storage = $this;
 		}
 		if (!isset($this->propagator)) {
 			$this->propagator = new HomePropagator($storage, \OC::$server->getDatabaseConnection());
 		}
-		/** @var \OC\Files\Cache\Propagator */
 		return $this->propagator;
 	}
 
 
-	/**
-	 * Returns the owner of this home storage
-	 *
-	 * @return \OC\User\User owner of this home storage
-	 */
 	public function getUser(): IUser {
 		return $this->user;
 	}
diff --git a/lib/private/Files/Storage/Local.php b/lib/private/Files/Storage/Local.php
index 5b1dcb623ba7a..8e7b258e14c8b 100644
--- a/lib/private/Files/Storage/Local.php
+++ b/lib/private/Files/Storage/Local.php
@@ -74,11 +74,11 @@ public function __construct($arguments) {
 	public function __destruct() {
 	}
 
-	public function getId() {
+	public function getId(): string {
 		return 'local::' . $this->datadir;
 	}
 
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		$sourcePath = $this->getSourcePath($path);
 		$oldMask = umask($this->defUMask);
 		$result = @mkdir($sourcePath, 0777, true);
@@ -86,7 +86,7 @@ public function mkdir($path) {
 		return $result;
 	}
 
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		if (!$this->isDeletable($path)) {
 			return false;
 		}
@@ -129,7 +129,7 @@ public function opendir($path) {
 		return opendir($this->getSourcePath($path));
 	}
 
-	public function is_dir($path) {
+	public function is_dir($path): bool {
 		if ($this->caseInsensitive && !$this->file_exists($path)) {
 			return false;
 		}
@@ -139,14 +139,14 @@ public function is_dir($path) {
 		return is_dir($this->getSourcePath($path));
 	}
 
-	public function is_file($path) {
+	public function is_file($path): bool {
 		if ($this->caseInsensitive && !$this->file_exists($path)) {
 			return false;
 		}
 		return is_file($this->getSourcePath($path));
 	}
 
-	public function stat($path) {
+	public function stat($path): array|false {
 		$fullPath = $this->getSourcePath($path);
 		clearstatcache(true, $fullPath);
 		if (!file_exists($fullPath)) {
@@ -164,7 +164,7 @@ public function stat($path) {
 		return $statResult;
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		try {
 			$stat = $this->stat($path);
 		} catch (ForbiddenException $e) {
@@ -213,7 +213,7 @@ public function getMetaData($path) {
 		return $data;
 	}
 
-	public function filetype($path) {
+	public function filetype($path): bool|string {
 		$filetype = filetype($this->getSourcePath($path));
 		if ($filetype == 'link') {
 			$filetype = filetype(realpath($this->getSourcePath($path)));
@@ -233,15 +233,15 @@ public function filesize($path): false|int|float {
 		return filesize($fullPath);
 	}
 
-	public function isReadable($path) {
+	public function isReadable($path): bool {
 		return is_readable($this->getSourcePath($path));
 	}
 
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		return is_writable($this->getSourcePath($path));
 	}
 
-	public function file_exists($path) {
+	public function file_exists($path): bool {
 		if ($this->caseInsensitive) {
 			$fullPath = $this->getSourcePath($path);
 			$parentPath = dirname($fullPath);
@@ -255,7 +255,7 @@ public function file_exists($path) {
 		}
 	}
 
-	public function filemtime($path) {
+	public function filemtime($path): false|int {
 		$fullPath = $this->getSourcePath($path);
 		clearstatcache(true, $fullPath);
 		if (!$this->file_exists($path)) {
@@ -268,7 +268,7 @@ public function filemtime($path) {
 		return filemtime($fullPath);
 	}
 
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		// sets the modification time of the file to the given value.
 		// If mtime is nil the current time is set.
 		// note that the access time of the file always changes to the current time.
@@ -289,11 +289,11 @@ public function touch($path, $mtime = null) {
 		return $result;
 	}
 
-	public function file_get_contents($path) {
+	public function file_get_contents($path): bool|string {
 		return file_get_contents($this->getSourcePath($path));
 	}
 
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): float|bool|int {
 		$oldMask = umask($this->defUMask);
 		if ($this->unlinkOnTruncate) {
 			$this->unlink($path);
@@ -303,7 +303,7 @@ public function file_put_contents($path, $data) {
 		return $result;
 	}
 
-	public function unlink($path) {
+	public function unlink($path): bool {
 		if ($this->is_dir($path)) {
 			return $this->rmdir($path);
 		} elseif ($this->is_file($path)) {
@@ -313,7 +313,7 @@ public function unlink($path) {
 		}
 	}
 
-	private function checkTreeForForbiddenItems(string $path) {
+	private function checkTreeForForbiddenItems(string $path): void {
 		$iterator = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($path));
 		foreach ($iterator as $file) {
 			/** @var \SplFileInfo $file */
@@ -364,7 +364,7 @@ public function rename($source, $target): bool {
 		return $this->copy($source, $target) && $this->unlink($source);
 	}
 
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		if ($this->is_dir($source)) {
 			return parent::copy($source, $target);
 		} else {
@@ -401,7 +401,7 @@ public function hash($type, $path, $raw = false): string|false {
 		return hash_file($type, $this->getSourcePath($path), $raw);
 	}
 
-	public function free_space($path) {
+	public function free_space($path): float|bool|int {
 		$sourcePath = $this->getSourcePath($path);
 		// using !is_dir because $sourcePath might be a part file or
 		// non-existing file, so we'd still want to use the parent dir
@@ -417,20 +417,19 @@ public function free_space($path) {
 		return Util::numericToNumber($space);
 	}
 
-	public function search($query) {
+	public function search($query): array {
 		return $this->searchInDir($query);
 	}
 
-	public function getLocalFile($path) {
+	public function getLocalFile($path): bool|string {
 		return $this->getSourcePath($path);
 	}
 
 	/**
 	 * @param string $query
 	 * @param string $dir
-	 * @return array
 	 */
-	protected function searchInDir($query, $dir = '') {
+	protected function searchInDir($query, $dir = ''): array {
 		$files = [];
 		$physicalDir = $this->getSourcePath($dir);
 		foreach (scandir($physicalDir) as $item) {
@@ -449,14 +448,7 @@ protected function searchInDir($query, $dir = '') {
 		return $files;
 	}
 
-	/**
-	 * check if a file or folder has been updated since $time
-	 *
-	 * @param string $path
-	 * @param int $time
-	 * @return bool
-	 */
-	public function hasUpdated($path, $time) {
+	public function hasUpdated($path, $time): bool {
 		if ($this->file_exists($path)) {
 			return $this->filemtime($path) > $time;
 		} else {
@@ -468,10 +460,9 @@ public function hasUpdated($path, $time) {
 	 * Get the source path (on disk) of a given path
 	 *
 	 * @param string $path
-	 * @return string
 	 * @throws ForbiddenException
 	 */
-	public function getSourcePath($path) {
+	public function getSourcePath($path): string {
 		if (Filesystem::isFileBlacklisted($path)) {
 			throw new ForbiddenException('Invalid path: ' . $path, false);
 		}
@@ -503,14 +494,11 @@ public function getSourcePath($path) {
 		throw new ForbiddenException('Following symlinks is not allowed', false);
 	}
 
-	/**
-	 * {@inheritdoc}
-	 */
-	public function isLocal() {
+	public function isLocal(): bool {
 		return true;
 	}
 
-	public function getETag($path) {
+	public function getETag($path): bool|string {
 		return $this->calculateEtag($path, $this->stat($path));
 	}
 
@@ -540,7 +528,7 @@ private function calculateEtag(string $path, array $stat): string|false {
 		}
 	}
 
-	private function canDoCrossStorageMove(IStorage $sourceStorage) {
+	private function canDoCrossStorageMove(IStorage $sourceStorage): bool {
 		/** @psalm-suppress UndefinedClass */
 		return $sourceStorage->instanceOfStorage(Local::class)
 			// Don't treat ACLStorageWrapper like local storage where copy can be done directly.
@@ -553,14 +541,7 @@ private function canDoCrossStorageMove(IStorage $sourceStorage) {
 			&& !$sourceStorage->instanceOfStorage(Encryption::class);
 	}
 
-	/**
-	 * @param IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @param bool $preserveMtime
-	 * @return bool
-	 */
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = false) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = false): bool {
 		if ($this->canDoCrossStorageMove($sourceStorage)) {
 			if ($sourceStorage->instanceOfStorage(Jail::class)) {
 				/**
@@ -584,7 +565,7 @@ public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 	 * @param string $targetInternalPath
 	 * @return bool
 	 */
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if ($this->canDoCrossStorageMove($sourceStorage)) {
 			if ($sourceStorage->instanceOfStorage(Jail::class)) {
 				/**
diff --git a/lib/private/Files/Storage/LocalRootStorage.php b/lib/private/Files/Storage/LocalRootStorage.php
index ae0575fe0430a..b44467964d671 100644
--- a/lib/private/Files/Storage/LocalRootStorage.php
+++ b/lib/private/Files/Storage/LocalRootStorage.php
@@ -9,9 +9,10 @@
 namespace OC\Files\Storage;
 
 use OC\Files\Cache\LocalRootScanner;
+use OCP\Files\Cache\IScanner;
 
 class LocalRootStorage extends Local {
-	public function getScanner($path = '', $storage = null) {
+	public function getScanner($path = '', $storage = null): IScanner {
 		if (!$storage) {
 			$storage = $this;
 		}
diff --git a/lib/private/Files/Storage/LocalTempFileTrait.php b/lib/private/Files/Storage/LocalTempFileTrait.php
index 26fbcc238fd49..057970dea8f22 100644
--- a/lib/private/Files/Storage/LocalTempFileTrait.php
+++ b/lib/private/Files/Storage/LocalTempFileTrait.php
@@ -32,7 +32,7 @@ protected function getCachedFile(string $path): string|false {
 	/**
 	 * @param string $path
 	 */
-	protected function removeCachedFile($path) {
+	protected function removeCachedFile($path): void {
 		unset($this->cachedFiles[$path]);
 	}
 
diff --git a/lib/private/Files/Storage/PolyFill/CopyDirectory.php b/lib/private/Files/Storage/PolyFill/CopyDirectory.php
index 5fe396d97e1d1..614432f0363d3 100644
--- a/lib/private/Files/Storage/PolyFill/CopyDirectory.php
+++ b/lib/private/Files/Storage/PolyFill/CopyDirectory.php
@@ -12,31 +12,28 @@ trait CopyDirectory {
 	 * Check if a path is a directory
 	 *
 	 * @param string $path
-	 * @return bool
 	 */
-	abstract public function is_dir($path);
+	abstract public function is_dir($path): bool;
 
 	/**
 	 * Check if a file or folder exists
 	 *
 	 * @param string $path
-	 * @return bool
 	 */
-	abstract public function file_exists($path);
+	abstract public function file_exists($path): bool;
 
 	/**
 	 * Delete a file or folder
 	 *
 	 * @param string $path
-	 * @return bool
 	 */
-	abstract public function unlink($path);
+	abstract public function unlink($path): bool;
 
 	/**
 	 * Open a directory handle for a folder
 	 *
 	 * @param string $path
-	 * @return resource | bool
+	 * @return resource|bool
 	 */
 	abstract public function opendir($path);
 
@@ -44,11 +41,10 @@ abstract public function opendir($path);
 	 * Create a new folder
 	 *
 	 * @param string $path
-	 * @return bool
 	 */
-	abstract public function mkdir($path);
+	abstract public function mkdir($path): bool;
 
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		if ($this->is_dir($source)) {
 			if ($this->file_exists($target)) {
 				$this->unlink($target);
@@ -62,12 +58,8 @@ public function copy($source, $target) {
 
 	/**
 	 * For adapters that don't support copying folders natively
-	 *
-	 * @param $source
-	 * @param $target
-	 * @return bool
 	 */
-	protected function copyRecursive($source, $target) {
+	protected function copyRecursive($source, $target): bool {
 		$dh = $this->opendir($source);
 		$result = true;
 		while (($file = readdir($dh)) !== false) {
diff --git a/lib/private/Files/Storage/Storage.php b/lib/private/Files/Storage/Storage.php
index d6d1d26c35a84..9cdc70aaa5969 100644
--- a/lib/private/Files/Storage/Storage.php
+++ b/lib/private/Files/Storage/Storage.php
@@ -8,11 +8,11 @@
 
 namespace OC\Files\Storage;
 
-use OC\Files\Cache\Cache;
-use OC\Files\Cache\Propagator;
-use OC\Files\Cache\Scanner;
-use OC\Files\Cache\Updater;
-use OC\Files\Cache\Watcher;
+use OCP\Files\Cache\ICache;
+use OCP\Files\Cache\IPropagator;
+use OCP\Files\Cache\IScanner;
+use OCP\Files\Cache\IUpdater;
+use OCP\Files\Cache\IWatcher;
 use OCP\Files\Storage\ILockingStorage;
 use OCP\Files\Storage\IStorage;
 
@@ -22,53 +22,23 @@
  * All paths passed to the storage are relative to the storage and should NOT have a leading slash.
  */
 interface Storage extends IStorage, ILockingStorage {
-	/**
-	 * @inheritDoc
-	 * @return Cache
-	 */
-	public function getCache($path = '', $storage = null);
+	public function getCache($path = '', $storage = null): ICache;
 
-	/**
-	 * @inheritDoc
-	 * @return Scanner
-	 */
-	public function getScanner($path = '', $storage = null);
+	public function getScanner($path = '', $storage = null): IScanner;
 
-	/**
-	 * @inheritDoc
-	 * @return Watcher
-	 */
-	public function getWatcher($path = '', $storage = null);
+	public function getWatcher($path = '', $storage = null): IWatcher;
 
-	/**
-	 * @inheritDoc
-	 * @return Propagator
-	 */
-	public function getPropagator($storage = null);
+	public function getPropagator($storage = null): IPropagator;
 
-	/**
-	 * @inheritDoc
-	 * @return Updater
-	 */
-	public function getUpdater($storage = null);
+	public function getUpdater($storage = null): IUpdater;
 
-	/**
-	 * @return \OC\Files\Cache\Storage
-	 */
-	public function getStorageCache();
+	public function getStorageCache(): \OC\Files\Cache\Storage;
 
-	/**
-	 * @param string $path
-	 * @return array|null
-	 */
-	public function getMetaData($path);
+	public function getMetaData($path): ?array;
 
 	/**
 	 * Get the contents of a directory with metadata
 	 *
-	 * @param string $directory
-	 * @return \Traversable an iterator, containing file metadata
-	 *
 	 * The metadata array will contain the following fields
 	 *
 	 * - name
@@ -79,5 +49,5 @@ public function getMetaData($path);
 	 * - storage_mtime
 	 * - permissions
 	 */
-	public function getDirectoryContent($directory): \Traversable;
+	public function getDirectoryContent($directory): \Traversable|false;
 }
diff --git a/lib/private/Files/Storage/StorageFactory.php b/lib/private/Files/Storage/StorageFactory.php
index 590425f5b641b..16fbc736535b7 100644
--- a/lib/private/Files/Storage/StorageFactory.php
+++ b/lib/private/Files/Storage/StorageFactory.php
@@ -17,19 +17,7 @@ class StorageFactory implements IStorageFactory {
 	 */
 	private $storageWrappers = [];
 
-	/**
-	 * allow modifier storage behaviour by adding wrappers around storages
-	 *
-	 * $callback should be a function of type (string $mountPoint, Storage $storage) => Storage
-	 *
-	 * @param string $wrapperName name of the wrapper
-	 * @param callable $callback callback
-	 * @param int $priority wrappers with the lower priority are applied last (meaning they get called first)
-	 * @param \OCP\Files\Mount\IMountPoint[] $existingMounts existing mount points to apply the wrapper to
-	 * @return bool true if the wrapper was added, false if there was already a wrapper with this
-	 *              name registered
-	 */
-	public function addStorageWrapper($wrapperName, $callback, $priority = 50, $existingMounts = []) {
+	public function addStorageWrapper($wrapperName, $callback, $priority = 50, $existingMounts = []): bool {
 		if (isset($this->storageWrappers[$wrapperName])) {
 			return false;
 		}
@@ -50,26 +38,18 @@ public function addStorageWrapper($wrapperName, $callback, $priority = 50, $exis
 	 * @param string $wrapperName name of the wrapper
 	 * @internal
 	 */
-	public function removeStorageWrapper($wrapperName) {
+	public function removeStorageWrapper($wrapperName): void {
 		unset($this->storageWrappers[$wrapperName]);
 	}
 
-	/**
-	 * Create an instance of a storage and apply the registered storage wrappers
-	 *
-	 * @param string $class
-	 * @param array $arguments
-	 * @return IStorage
-	 */
-	public function getInstance(IMountPoint $mountPoint, $class, $arguments) {
+	public function getInstance(IMountPoint $mountPoint, $class, $arguments): IStorage {
 		return $this->wrap($mountPoint, new $class($arguments));
 	}
 
 	/**
 	 * @param IStorage $storage
-	 * @return IStorage
 	 */
-	public function wrap(IMountPoint $mountPoint, $storage) {
+	public function wrap(IMountPoint $mountPoint, $storage): IStorage {
 		$wrappers = array_values($this->storageWrappers);
 		usort($wrappers, function ($a, $b) {
 			return $b['priority'] - $a['priority'];
diff --git a/lib/private/Files/Storage/Temporary.php b/lib/private/Files/Storage/Temporary.php
index 6c7ef4260c192..429f0fd1e92db 100644
--- a/lib/private/Files/Storage/Temporary.php
+++ b/lib/private/Files/Storage/Temporary.php
@@ -15,7 +15,7 @@ public function __construct($arguments = []) {
 		parent::__construct(['datadir' => \OC::$server->getTempManager()->getTemporaryFolder()]);
 	}
 
-	public function cleanUp() {
+	public function cleanUp(): void {
 		\OC_Helper::rmdirr($this->datadir);
 	}
 
@@ -24,7 +24,7 @@ public function __destruct() {
 		$this->cleanUp();
 	}
 
-	public function getDataDir() {
+	public function getDataDir(): array|string {
 		return $this->datadir;
 	}
 }
diff --git a/lib/private/Files/Storage/Wrapper/Availability.php b/lib/private/Files/Storage/Wrapper/Availability.php
index aaf0acdc74f7b..82a502c08f247 100644
--- a/lib/private/Files/Storage/Wrapper/Availability.php
+++ b/lib/private/Files/Storage/Wrapper/Availability.php
@@ -28,7 +28,7 @@ public function __construct($parameters) {
 		parent::__construct($parameters);
 	}
 
-	public static function shouldRecheck($availability) {
+	public static function shouldRecheck($availability): bool {
 		if (!$availability['available']) {
 			// trigger a recheck if TTL reached
 			if ((time() - $availability['last_checked']) > self::RECHECK_TTL_SEC) {
@@ -40,10 +40,8 @@ public static function shouldRecheck($availability) {
 
 	/**
 	 * Only called if availability === false
-	 *
-	 * @return bool
 	 */
-	private function updateAvailability() {
+	private function updateAvailability(): bool {
 		// reset availability to false so that multiple requests don't recheck concurrently
 		$this->setAvailability(false);
 		try {
@@ -55,10 +53,7 @@ private function updateAvailability() {
 		return $result;
 	}
 
-	/**
-	 * @return bool
-	 */
-	private function isAvailable() {
+	private function isAvailable(): bool {
 		$availability = $this->getAvailability();
 		if (self::shouldRecheck($availability)) {
 			return $this->updateAvailability();
@@ -69,154 +64,153 @@ private function isAvailable() {
 	/**
 	 * @throws StorageNotAvailableException
 	 */
-	private function checkAvailability() {
+	private function checkAvailability(): void {
 		if (!$this->isAvailable()) {
 			throw new StorageNotAvailableException();
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::mkdir($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::rmdir($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
 	public function opendir($path) {
 		$this->checkAvailability();
 		try {
 			return parent::opendir($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function is_dir($path) {
+	public function is_dir($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::is_dir($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function is_file($path) {
+	public function is_file($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::is_file($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function stat($path) {
+	public function stat($path): array|false {
 		$this->checkAvailability();
 		try {
 			return parent::stat($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function filetype($path) {
+	public function filetype($path): string|false {
 		$this->checkAvailability();
 		try {
 			return parent::filetype($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
 	public function filesize($path): false|int|float {
 		$this->checkAvailability();
 		try {
 			return parent::filesize($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function isCreatable($path) {
+	public function isCreatable($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::isCreatable($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function isReadable($path) {
+	public function isReadable($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::isReadable($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::isUpdatable($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function isDeletable($path) {
+	public function isDeletable($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::isDeletable($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function isSharable($path) {
+	public function isSharable($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::isSharable($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function getPermissions($path) {
+	public function getPermissions($path): int {
 		$this->checkAvailability();
 		try {
 			return parent::getPermissions($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return 0;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function file_exists($path) {
+	public function file_exists($path): bool {
 		if ($path === '') {
 			return true;
 		}
@@ -225,91 +219,91 @@ public function file_exists($path) {
 			return parent::file_exists($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function filemtime($path) {
+	public function filemtime($path): int|false {
 		$this->checkAvailability();
 		try {
 			return parent::filemtime($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function file_get_contents($path) {
+	public function file_get_contents($path): string|false {
 		$this->checkAvailability();
 		try {
 			return parent::file_get_contents($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): int|float|false {
 		$this->checkAvailability();
 		try {
 			return parent::file_put_contents($path, $data);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function unlink($path) {
+	public function unlink($path): bool {
 		$this->checkAvailability();
 		try {
 			return parent::unlink($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		$this->checkAvailability();
 		try {
 			return parent::rename($source, $target);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		$this->checkAvailability();
 		try {
 			return parent::copy($source, $target);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
 	public function fopen($path, $mode) {
 		$this->checkAvailability();
 		try {
 			return parent::fopen($path, $mode);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function getMimeType($path) {
+	public function getMimeType($path): string|false {
 		$this->checkAvailability();
 		try {
 			return parent::getMimeType($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function hash($type, $path, $raw = false) {
+	public function hash($type, $path, $raw = false): string|false {
 		$this->checkAvailability();
 		try {
 			return parent::hash($type, $path, $raw);
@@ -319,48 +313,37 @@ public function hash($type, $path, $raw = false) {
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function free_space($path) {
+	public function free_space($path): int|float|false {
 		$this->checkAvailability();
 		try {
 			return parent::free_space($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function search($query) {
-		$this->checkAvailability();
-		try {
-			return parent::search($query);
-		} catch (StorageNotAvailableException $e) {
-			$this->setUnavailable($e);
-		}
-	}
-
-	/** {@inheritdoc} */
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		$this->checkAvailability();
 		try {
 			return parent::touch($path, $mtime);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function getLocalFile($path) {
+	public function getLocalFile($path): string|false {
 		$this->checkAvailability();
 		try {
 			return parent::getLocalFile($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function hasUpdated($path, $time) {
+	public function hasUpdated($path, $time): bool {
 		if (!$this->isAvailable()) {
 			return false;
 		}
@@ -382,52 +365,53 @@ public function getOwner($path): string|false {
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function getETag($path) {
+	public function getETag($path): string|false {
 		$this->checkAvailability();
 		try {
 			return parent::getETag($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function getDirectDownload($path) {
+	public function getDirectDownload($path): array|false {
 		$this->checkAvailability();
 		try {
 			return parent::getDirectDownload($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		$this->checkAvailability();
 		try {
 			return parent::copyFromStorage($sourceStorage, $sourceInternalPath, $targetInternalPath);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	/** {@inheritdoc} */
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		$this->checkAvailability();
 		try {
 			return parent::moveFromStorage($sourceStorage, $sourceInternalPath, $targetInternalPath);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		$this->checkAvailability();
 		try {
 			return parent::getMetaData($path);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return null;
 		}
 	}
 
@@ -454,12 +438,13 @@ protected function setUnavailable(?StorageNotAvailableException $e): void {
 
 
 
-	public function getDirectoryContent($directory): \Traversable {
+	public function getDirectoryContent($directory): \Traversable|false {
 		$this->checkAvailability();
 		try {
 			return parent::getDirectoryContent($directory);
 		} catch (StorageNotAvailableException $e) {
 			$this->setUnavailable($e);
+			return false;
 		}
 	}
 }
diff --git a/lib/private/Files/Storage/Wrapper/Encoding.php b/lib/private/Files/Storage/Wrapper/Encoding.php
index 48c6c38c8483f..26e0e3a15ddd4 100644
--- a/lib/private/Files/Storage/Wrapper/Encoding.php
+++ b/lib/private/Files/Storage/Wrapper/Encoding.php
@@ -9,6 +9,7 @@
 
 use OC\Files\Filesystem;
 use OCP\Cache\CappedMemoryCache;
+use OCP\Files\Cache\IScanner;
 use OCP\Files\Storage\IStorage;
 use OCP\ICache;
 
@@ -36,10 +37,8 @@ public function __construct($parameters) {
 	 * Returns whether the given string is only made of ASCII characters
 	 *
 	 * @param string $str string
-	 *
-	 * @return bool true if the string is all ASCII, false otherwise
 	 */
-	private function isAscii($str) {
+	private function isAscii($str): bool {
 		return !preg_match('/[\\x80-\\xff]+/', $str);
 	}
 
@@ -52,7 +51,7 @@ private function isAscii($str) {
 	 *
 	 * @return string original or converted path
 	 */
-	private function findPathToUse($fullPath) {
+	private function findPathToUse($fullPath): string {
 		$cachedPath = $this->namesCache[$fullPath];
 		if ($cachedPath !== null) {
 			return $cachedPath;
@@ -81,7 +80,7 @@ private function findPathToUse($fullPath) {
 	 *
 	 * @return string|null original or converted path, or null if none of the forms was found
 	 */
-	private function findPathToUseLastSection($basePath, $lastSection) {
+	private function findPathToUseLastSection($basePath, $lastSection): ?string {
 		$fullPath = $basePath . $lastSection;
 		if ($lastSection === '' || $this->isAscii($lastSection) || $this->storage->file_exists($fullPath)) {
 			$this->namesCache[$fullPath] = $fullPath;
@@ -105,13 +104,7 @@ private function findPathToUseLastSection($basePath, $lastSection) {
 		return null;
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.mkdir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		// note: no conversion here, method should not be called with non-NFC names!
 		$result = $this->storage->mkdir($path);
 		if ($result) {
@@ -120,13 +113,7 @@ public function mkdir($path) {
 		return $result;
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.rmdir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		$result = $this->storage->rmdir($this->findPathToUse($path));
 		if ($result) {
 			unset($this->namesCache[$path]);
@@ -134,175 +121,72 @@ public function rmdir($path) {
 		return $result;
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.opendir.php
-	 *
-	 * @param string $path
-	 * @return resource|false
-	 */
 	public function opendir($path) {
 		$handle = $this->storage->opendir($this->findPathToUse($path));
 		return EncodingDirectoryWrapper::wrap($handle);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.is_dir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function is_dir($path) {
+	public function is_dir($path): bool {
 		return $this->storage->is_dir($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.is_file.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function is_file($path) {
+	public function is_file($path): bool {
 		return $this->storage->is_file($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.stat.php
-	 * only the following keys are required in the result: size and mtime
-	 *
-	 * @param string $path
-	 * @return array|bool
-	 */
-	public function stat($path) {
+	public function stat($path): array|false {
 		return $this->storage->stat($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filetype.php
-	 *
-	 * @param string $path
-	 * @return string|bool
-	 */
-	public function filetype($path) {
+	public function filetype($path): string|false {
 		return $this->storage->filetype($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filesize.php
-	 * The result for filesize when called on a folder is required to be 0
-	 */
-	public function filesize($path): false|int|float {
+	public function filesize($path): int|float|false {
 		return $this->storage->filesize($this->findPathToUse($path));
 	}
 
-	/**
-	 * check if a file can be created in $path
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isCreatable($path) {
+	public function isCreatable($path): bool {
 		return $this->storage->isCreatable($this->findPathToUse($path));
 	}
 
-	/**
-	 * check if a file can be read
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isReadable($path) {
+	public function isReadable($path): bool {
 		return $this->storage->isReadable($this->findPathToUse($path));
 	}
 
-	/**
-	 * check if a file can be written to
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		return $this->storage->isUpdatable($this->findPathToUse($path));
 	}
 
-	/**
-	 * check if a file can be deleted
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isDeletable($path) {
+	public function isDeletable($path): bool {
 		return $this->storage->isDeletable($this->findPathToUse($path));
 	}
 
-	/**
-	 * check if a file can be shared
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isSharable($path) {
+	public function isSharable($path): bool {
 		return $this->storage->isSharable($this->findPathToUse($path));
 	}
 
-	/**
-	 * get the full permissions of a path.
-	 * Should return a combination of the PERMISSION_ constants defined in lib/public/constants.php
-	 *
-	 * @param string $path
-	 * @return int
-	 */
-	public function getPermissions($path) {
+	public function getPermissions($path): int {
 		return $this->storage->getPermissions($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_exists.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function file_exists($path) {
+	public function file_exists($path): bool {
 		return $this->storage->file_exists($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filemtime.php
-	 *
-	 * @param string $path
-	 * @return int|bool
-	 */
-	public function filemtime($path) {
+	public function filemtime($path): int|false {
 		return $this->storage->filemtime($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_get_contents.php
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function file_get_contents($path) {
+	public function file_get_contents($path): string|false {
 		return $this->storage->file_get_contents($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_put_contents.php
-	 *
-	 * @param string $path
-	 * @param mixed $data
-	 * @return int|float|false
-	 */
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): int|float|false {
 		return $this->storage->file_put_contents($this->findPathToUse($path), $data);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.unlink.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function unlink($path) {
+	public function unlink($path): bool {
 		$result = $this->storage->unlink($this->findPathToUse($path));
 		if ($result) {
 			unset($this->namesCache[$path]);
@@ -310,36 +194,15 @@ public function unlink($path) {
 		return $result;
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.rename.php
-	 *
-	 * @param string $source
-	 * @param string $target
-	 * @return bool
-	 */
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		// second name always NFC
 		return $this->storage->rename($this->findPathToUse($source), $this->findPathToUse($target));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.copy.php
-	 *
-	 * @param string $source
-	 * @param string $target
-	 * @return bool
-	 */
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		return $this->storage->copy($this->findPathToUse($source), $this->findPathToUse($target));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.fopen.php
-	 *
-	 * @param string $path
-	 * @param string $mode
-	 * @return resource|bool
-	 */
 	public function fopen($path, $mode) {
 		$result = $this->storage->fopen($this->findPathToUse($path), $mode);
 		if ($result && $mode !== 'r' && $mode !== 'rb') {
@@ -348,107 +211,49 @@ public function fopen($path, $mode) {
 		return $result;
 	}
 
-	/**
-	 * get the mimetype for a file or folder
-	 * The mimetype for a folder is required to be "httpd/unix-directory"
-	 *
-	 * @param string $path
-	 * @return string|bool
-	 */
-	public function getMimeType($path) {
+	public function getMimeType($path): string|false {
 		return $this->storage->getMimeType($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.hash.php
-	 *
-	 * @param string $type
-	 * @param string $path
-	 * @param bool $raw
-	 * @return string|bool
-	 */
-	public function hash($type, $path, $raw = false) {
+	public function hash($type, $path, $raw = false): string|false {
 		return $this->storage->hash($type, $this->findPathToUse($path), $raw);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.free_space.php
-	 *
-	 * @param string $path
-	 * @return int|float|bool
-	 */
-	public function free_space($path) {
+	public function free_space($path): int|float|false {
 		return $this->storage->free_space($this->findPathToUse($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.touch.php
-	 * If the backend does not support the operation, false should be returned
-	 *
-	 * @param string $path
-	 * @param int $mtime
-	 * @return bool
-	 */
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		return $this->storage->touch($this->findPathToUse($path), $mtime);
 	}
 
-	/**
-	 * get the path to a local version of the file.
-	 * The local version of the file can be temporary and doesn't have to be persistent across requests
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function getLocalFile($path) {
+	public function getLocalFile($path): string|false {
 		return $this->storage->getLocalFile($this->findPathToUse($path));
 	}
 
-	/**
-	 * check if a file or folder has been updated since $time
-	 *
-	 * @param string $path
-	 * @param int $time
-	 * @return bool
-	 *
-	 * hasUpdated for folders should return at least true if a file inside the folder is add, removed or renamed.
-	 * returning true for other changes in the folder is optional
-	 */
-	public function hasUpdated($path, $time) {
+	public function hasUpdated($path, $time): bool {
 		return $this->storage->hasUpdated($this->findPathToUse($path), $time);
 	}
 
-	public function getCache($path = '', $storage = null) {
+	public function getCache($path = '', $storage = null): \OCP\Files\Cache\ICache {
 		if (!$storage) {
 			$storage = $this;
 		}
 		return $this->storage->getCache($this->findPathToUse($path), $storage);
 	}
 
-	public function getScanner($path = '', $storage = null) {
+	public function getScanner($path = '', $storage = null): IScanner {
 		if (!$storage) {
 			$storage = $this;
 		}
 		return $this->storage->getScanner($this->findPathToUse($path), $storage);
 	}
 
-	/**
-	 * get the ETag for a file or folder
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function getETag($path) {
+	public function getETag($path): string|false {
 		return $this->storage->getETag($this->findPathToUse($path));
 	}
 
-	/**
-	 * @param IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @return bool
-	 */
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if ($sourceStorage === $this) {
 			return $this->copy($sourceInternalPath, $this->findPathToUse($targetInternalPath));
 		}
@@ -460,13 +265,7 @@ public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 		return $result;
 	}
 
-	/**
-	 * @param IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @return bool
-	 */
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if ($sourceStorage === $this) {
 			$result = $this->rename($sourceInternalPath, $this->findPathToUse($targetInternalPath));
 			if ($result) {
@@ -484,7 +283,7 @@ public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 		return $result;
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		$entry = $this->storage->getMetaData($this->findPathToUse($path));
 		$entry['name'] = trim(Filesystem::normalizePath($entry['name']), '/');
 		return $entry;
diff --git a/lib/private/Files/Storage/Wrapper/EncodingDirectoryWrapper.php b/lib/private/Files/Storage/Wrapper/EncodingDirectoryWrapper.php
index 26b32d9aa6285..0a90b49f0f153 100644
--- a/lib/private/Files/Storage/Wrapper/EncodingDirectoryWrapper.php
+++ b/lib/private/Files/Storage/Wrapper/EncodingDirectoryWrapper.php
@@ -13,11 +13,7 @@
  * Normalize file names while reading directory entries
  */
 class EncodingDirectoryWrapper extends DirectoryWrapper {
-	/**
-	 * @psalm-suppress ImplementedReturnTypeMismatch Until return type is fixed upstream
-	 * @return string|false
-	 */
-	public function dir_readdir() {
+	public function dir_readdir(): string|false {
 		$file = readdir($this->source);
 		if ($file !== false && $file !== '.' && $file !== '..') {
 			$file = trim(Filesystem::normalizePath($file), '/');
@@ -28,7 +24,6 @@ public function dir_readdir() {
 
 	/**
 	 * @param resource $source
-	 * @param callable $filter
 	 * @return resource|false
 	 */
 	public static function wrap($source) {
diff --git a/lib/private/Files/Storage/Wrapper/Encryption.php b/lib/private/Files/Storage/Wrapper/Encryption.php
index 3b45e996f5de5..728e9c46413c6 100644
--- a/lib/private/Files/Storage/Wrapper/Encryption.php
+++ b/lib/private/Files/Storage/Wrapper/Encryption.php
@@ -18,7 +18,6 @@
 use OC\Files\Storage\LocalTempFileTrait;
 use OC\Memcache\ArrayCache;
 use OCP\Cache\CappedMemoryCache;
-use OCP\Encryption\Exceptions\GenericEncryptionException;
 use OCP\Encryption\IFile;
 use OCP\Encryption\IManager;
 use OCP\Encryption\Keys\IStorage;
@@ -104,10 +103,6 @@ public function __construct(
 		parent::__construct($parameters);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filesize.php
-	 * The result for filesize when called on a folder is required to be 0
-	 */
 	public function filesize($path): false|int|float {
 		$fullPath = $this->getFullPath($path);
 
@@ -179,7 +174,7 @@ private function modifyMetaData(string $path, array $data): array {
 		return $data;
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		$data = $this->storage->getMetaData($path);
 		if (is_null($data)) {
 			return null;
@@ -194,13 +189,7 @@ public function getDirectoryContent($directory): \Traversable {
 		}
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_get_contents.php
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function file_get_contents($path) {
+	public function file_get_contents($path): false|string {
 		$encryptionModule = $this->getEncryptionModule($path);
 
 		if ($encryptionModule) {
@@ -215,14 +204,7 @@ public function file_get_contents($path) {
 		return $this->storage->file_get_contents($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_put_contents.php
-	 *
-	 * @param string $path
-	 * @param mixed $data
-	 * @return int|false
-	 */
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): float|false|int {
 		// file put content will always be translated to a stream write
 		$handle = $this->fopen($path, 'w');
 		if (is_resource($handle)) {
@@ -234,13 +216,7 @@ public function file_put_contents($path, $data) {
 		return false;
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.unlink.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function unlink($path) {
+	public function unlink($path): bool {
 		$fullPath = $this->getFullPath($path);
 		if ($this->util->isExcluded($fullPath)) {
 			return $this->storage->unlink($path);
@@ -254,14 +230,7 @@ public function unlink($path) {
 		return $this->storage->unlink($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.rename.php
-	 *
-	 * @param string $source
-	 * @param string $target
-	 * @return bool
-	 */
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		$result = $this->storage->rename($source, $target);
 
 		if ($result &&
@@ -286,13 +255,7 @@ public function rename($source, $target) {
 		return $result;
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.rmdir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		$result = $this->storage->rmdir($path);
 		$fullPath = $this->getFullPath($path);
 		if ($result &&
@@ -305,13 +268,7 @@ public function rmdir($path) {
 		return $result;
 	}
 
-	/**
-	 * check if a file can be read
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isReadable($path) {
+	public function isReadable($path): bool {
 		$isReadable = true;
 
 		$metaData = $this->getMetaData($path);
@@ -328,12 +285,6 @@ public function isReadable($path) {
 		return $this->storage->isReadable($path) && $isReadable;
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.copy.php
-	 *
-	 * @param string $source
-	 * @param string $target
-	 */
 	public function copy($source, $target): bool {
 		$sourcePath = $this->getFullPath($source);
 
@@ -347,15 +298,6 @@ public function copy($source, $target): bool {
 		return $this->copyFromStorage($this, $source, $target);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.fopen.php
-	 *
-	 * @param string $path
-	 * @param string $mode
-	 * @return resource|bool
-	 * @throws GenericEncryptionException
-	 * @throws ModuleDoesNotExistsException
-	 */
 	public function fopen($path, $mode) {
 		// check if the file is stored in the array cache, this means that we
 		// copy a file over to the versions folder, in this case we don't want to
@@ -409,10 +351,8 @@ public function fopen($path, $mode) {
 					// if we update a encrypted file with a un-encrypted one we change the db flag
 					if ($targetIsEncrypted && $encryptionEnabled === false) {
 						$cache = $this->storage->getCache();
-						if ($cache) {
-							$entry = $cache->get($path);
-							$cache->update($entry->getId(), ['encrypted' => 0]);
-						}
+						$entry = $cache->get($path);
+						$cache->update($entry->getId(), ['encrypted' => 0]);
 					}
 					if ($encryptionEnabled) {
 						// if $encryptionModuleId is empty, the default module will be used
@@ -511,7 +451,7 @@ protected function verifyUnencryptedSize(string $path, int $unencryptedSize): in
 	 *
 	 * @return int calculated unencrypted size
 	 */
-	protected function fixUnencryptedSize(string $path, int $size, int $unencryptedSize): int {
+	protected function fixUnencryptedSize(string $path, int $size, int $unencryptedSize): float|int {
 		$headerSize = $this->getHeaderSize($path);
 		$header = $this->getHeader($path);
 		$encryptionModule = $this->getEncryptionModule($path);
@@ -580,12 +520,10 @@ protected function fixUnencryptedSize(string $path, int $size, int $unencryptedS
 
 		// write to cache if applicable
 		$cache = $this->storage->getCache();
-		if ($cache) {
-			$entry = $cache->get($path);
-			$cache->update($entry['fileid'], [
-				'unencrypted_size' => $newUnencryptedSize
-			]);
-		}
+		$entry = $cache->get($path);
+		$cache->update($entry['fileid'], [
+			'unencrypted_size' => $newUnencryptedSize
+		]);
 
 		return $newUnencryptedSize;
 	}
@@ -617,19 +555,12 @@ private function fread_block($handle, int $blockSize): string {
 		return $data;
 	}
 
-	/**
-	 * @param Storage\IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @param bool $preserveMtime
-	 * @return bool
-	 */
 	public function moveFromStorage(
 		Storage\IStorage $sourceStorage,
 		$sourceInternalPath,
 		$targetInternalPath,
 		$preserveMtime = true,
-	) {
+	): bool {
 		if ($sourceStorage === $this) {
 			return $this->rename($sourceInternalPath, $targetInternalPath);
 		}
@@ -655,22 +586,13 @@ public function moveFromStorage(
 		return $result;
 	}
 
-
-	/**
-	 * @param Storage\IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @param bool $preserveMtime
-	 * @param bool $isRename
-	 * @return bool
-	 */
 	public function copyFromStorage(
 		Storage\IStorage $sourceStorage,
 		$sourceInternalPath,
 		$targetInternalPath,
 		$preserveMtime = false,
 		$isRename = false,
-	) {
+	): bool {
 		// TODO clean this up once the underlying moveFromStorage in OC\Files\Storage\Wrapper\Common is fixed:
 		// - call $this->storage->copyFromStorage() instead of $this->copyBetweenStorage
 		// - copy the file cache update from  $this->copyBetweenStorage to this method
@@ -695,7 +617,7 @@ private function updateEncryptedVersion(
 		$targetInternalPath,
 		$isRename,
 		$keepEncryptionVersion,
-	) {
+	): void {
 		$isEncrypted = $this->encryptionManager->isEnabled() && $this->shouldEncrypt($targetInternalPath);
 		$cacheInformation = [
 			'encrypted' => $isEncrypted,
@@ -750,7 +672,7 @@ private function copyBetweenStorage(
 		$targetInternalPath,
 		$preserveMtime,
 		$isRename,
-	) {
+	): bool {
 		// for versions we have nothing to do, because versions should always use the
 		// key from the original file. Just create a 1:1 copy and done
 		if ($this->isVersion($targetInternalPath) ||
@@ -828,7 +750,7 @@ private function copyBetweenStorage(
 		return (bool)$result;
 	}
 
-	public function getLocalFile($path) {
+	public function getLocalFile($path): string|false {
 		if ($this->encryptionManager->isEnabled()) {
 			$cachedFile = $this->getCachedFile($path);
 			if (is_string($cachedFile)) {
@@ -838,14 +760,14 @@ public function getLocalFile($path) {
 		return $this->storage->getLocalFile($path);
 	}
 
-	public function isLocal() {
+	public function isLocal(): bool {
 		if ($this->encryptionManager->isEnabled()) {
 			return false;
 		}
 		return $this->storage->isLocal();
 	}
 
-	public function stat($path) {
+	public function stat($path): array|false {
 		$stat = $this->storage->stat($path);
 		if (!$stat) {
 			return false;
@@ -857,7 +779,7 @@ public function stat($path) {
 		return $stat;
 	}
 
-	public function hash($type, $path, $raw = false) {
+	public function hash($type, $path, $raw = false): false|string {
 		$fh = $this->fopen($path, 'rb');
 		$ctx = hash_init($type);
 		hash_update_stream($ctx, $fh);
@@ -871,7 +793,7 @@ public function hash($type, $path, $raw = false) {
 	 * @param string $path relative to mount point
 	 * @return string full path including mount point
 	 */
-	protected function getFullPath($path) {
+	protected function getFullPath($path): string {
 		return Filesystem::normalizePath($this->mountPoint . '/' . $path);
 	}
 
@@ -882,7 +804,7 @@ protected function getFullPath($path) {
 	 * @param string $path
 	 * @return string
 	 */
-	protected function readFirstBlock($path) {
+	protected function readFirstBlock($path): string {
 		$firstBlock = '';
 		if ($this->storage->is_file($path)) {
 			$handle = $this->storage->fopen($path, 'r');
@@ -898,7 +820,7 @@ protected function readFirstBlock($path) {
 	 * @param string $path
 	 * @return int
 	 */
-	protected function getHeaderSize($path) {
+	protected function getHeaderSize($path): int {
 		$headerSize = 0;
 		$realFile = $this->util->stripPartialFileExtension($path);
 		if ($this->storage->is_file($realFile)) {
@@ -919,7 +841,7 @@ protected function getHeaderSize($path) {
 	 * @param string $path
 	 * @return array
 	 */
-	protected function getHeader($path) {
+	protected function getHeader($path): array {
 		$realFile = $this->util->stripPartialFileExtension($path);
 		$exists = $this->storage->is_file($realFile);
 		if ($exists) {
@@ -956,7 +878,7 @@ protected function getHeader($path) {
 	 * @throws ModuleDoesNotExistsException
 	 * @throws \Exception
 	 */
-	protected function getEncryptionModule($path) {
+	protected function getEncryptionModule($path): ?\OCP\Encryption\IEncryptionModule {
 		$encryptionModule = null;
 		$header = $this->getHeader($path);
 		$encryptionModuleId = $this->util->getEncryptionModuleId($header);
@@ -976,7 +898,7 @@ protected function getEncryptionModule($path) {
 	 * @param string $path
 	 * @param int $unencryptedSize
 	 */
-	public function updateUnencryptedSize($path, $unencryptedSize) {
+	public function updateUnencryptedSize($path, $unencryptedSize): void {
 		$this->unencryptedSize[$path] = $unencryptedSize;
 	}
 
@@ -987,7 +909,7 @@ public function updateUnencryptedSize($path, $unencryptedSize) {
 	 * @param string $target path relative to data/
 	 * @return bool
 	 */
-	protected function copyKeys($source, $target) {
+	protected function copyKeys($source, $target): bool {
 		if (!$this->util->isExcluded($source)) {
 			return $this->keyStorage->copyKeys($source, $target);
 		}
@@ -1001,7 +923,7 @@ protected function copyKeys($source, $target) {
 	 * @param $path
 	 * @return bool
 	 */
-	protected function isVersion($path) {
+	protected function isVersion($path): bool {
 		$normalized = Filesystem::normalizePath($path);
 		return substr($normalized, 0, strlen('/files_versions/')) === '/files_versions/';
 	}
@@ -1012,7 +934,7 @@ protected function isVersion($path) {
 	 * @param $path
 	 * @return bool
 	 */
-	protected function shouldEncrypt($path) {
+	protected function shouldEncrypt($path): bool {
 		$fullPath = $this->getFullPath($path);
 		$mountPointConfig = $this->mount->getOption('encrypt', true);
 		if ($mountPointConfig === false) {
diff --git a/lib/private/Files/Storage/Wrapper/Jail.php b/lib/private/Files/Storage/Wrapper/Jail.php
index e61ded4bc380f..894908291c026 100644
--- a/lib/private/Files/Storage/Wrapper/Jail.php
+++ b/lib/private/Files/Storage/Wrapper/Jail.php
@@ -11,6 +11,9 @@
 use OC\Files\Cache\Wrapper\JailPropagator;
 use OC\Files\Cache\Wrapper\JailWatcher;
 use OC\Files\Filesystem;
+use OCP\Files\Cache\ICache;
+use OCP\Files\Cache\IPropagator;
+use OCP\Files\Cache\IWatcher;
 use OCP\Files\Storage\IStorage;
 use OCP\Files\Storage\IWriteStreamStorage;
 use OCP\Lock\ILockingProvider;
@@ -37,19 +40,19 @@ public function __construct($arguments) {
 		$this->rootPath = $arguments['root'];
 	}
 
-	public function getUnjailedPath($path) {
+	public function getUnjailedPath($path): string {
 		return trim(Filesystem::normalizePath($this->rootPath . '/' . $path), '/');
 	}
 
 	/**
 	 * This is separate from Wrapper::getWrapperStorage so we can get the jailed storage consistently even if the jail is inside another wrapper
 	 */
-	public function getUnjailedStorage() {
+	public function getUnjailedStorage(): IStorage {
 		return $this->storage;
 	}
 
 
-	public function getJailedPath($path) {
+	public function getJailedPath($path): ?string {
 		$root = rtrim($this->rootPath, '/') . '/';
 
 		if ($path !== $this->rootPath && !str_starts_with($path, $root)) {
@@ -60,305 +63,123 @@ public function getJailedPath($path) {
 		}
 	}
 
-	public function getId() {
+	public function getId(): string {
 		return parent::getId();
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.mkdir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		return $this->getWrapperStorage()->mkdir($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.rmdir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		return $this->getWrapperStorage()->rmdir($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.opendir.php
-	 *
-	 * @param string $path
-	 * @return resource|false
-	 */
 	public function opendir($path) {
 		return $this->getWrapperStorage()->opendir($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.is_dir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function is_dir($path) {
+	public function is_dir($path): bool {
 		return $this->getWrapperStorage()->is_dir($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.is_file.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function is_file($path) {
+	public function is_file($path): bool {
 		return $this->getWrapperStorage()->is_file($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.stat.php
-	 * only the following keys are required in the result: size and mtime
-	 *
-	 * @param string $path
-	 * @return array|bool
-	 */
-	public function stat($path) {
+	public function stat($path): array|false {
 		return $this->getWrapperStorage()->stat($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filetype.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function filetype($path) {
+	public function filetype($path): false|string {
 		return $this->getWrapperStorage()->filetype($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filesize.php
-	 * The result for filesize when called on a folder is required to be 0
-	 */
 	public function filesize($path): false|int|float {
 		return $this->getWrapperStorage()->filesize($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * check if a file can be created in $path
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isCreatable($path) {
+	public function isCreatable($path): bool {
 		return $this->getWrapperStorage()->isCreatable($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * check if a file can be read
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isReadable($path) {
+	public function isReadable($path): bool {
 		return $this->getWrapperStorage()->isReadable($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * check if a file can be written to
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		return $this->getWrapperStorage()->isUpdatable($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * check if a file can be deleted
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isDeletable($path) {
+	public function isDeletable($path): bool {
 		return $this->getWrapperStorage()->isDeletable($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * check if a file can be shared
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isSharable($path) {
+	public function isSharable($path): bool {
 		return $this->getWrapperStorage()->isSharable($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * get the full permissions of a path.
-	 * Should return a combination of the PERMISSION_ constants defined in lib/public/constants.php
-	 *
-	 * @param string $path
-	 * @return int
-	 */
-	public function getPermissions($path) {
+	public function getPermissions($path): int {
 		return $this->getWrapperStorage()->getPermissions($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_exists.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function file_exists($path) {
+	public function file_exists($path): bool {
 		return $this->getWrapperStorage()->file_exists($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filemtime.php
-	 *
-	 * @param string $path
-	 * @return int|bool
-	 */
-	public function filemtime($path) {
+	public function filemtime($path): false|int {
 		return $this->getWrapperStorage()->filemtime($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_get_contents.php
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function file_get_contents($path) {
+	public function file_get_contents($path): false|string {
 		return $this->getWrapperStorage()->file_get_contents($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_put_contents.php
-	 *
-	 * @param string $path
-	 * @param mixed $data
-	 * @return int|float|false
-	 */
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): float|false|int {
 		return $this->getWrapperStorage()->file_put_contents($this->getUnjailedPath($path), $data);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.unlink.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function unlink($path) {
+	public function unlink($path): bool {
 		return $this->getWrapperStorage()->unlink($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.rename.php
-	 *
-	 * @param string $source
-	 * @param string $target
-	 * @return bool
-	 */
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		return $this->getWrapperStorage()->rename($this->getUnjailedPath($source), $this->getUnjailedPath($target));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.copy.php
-	 *
-	 * @param string $source
-	 * @param string $target
-	 * @return bool
-	 */
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		return $this->getWrapperStorage()->copy($this->getUnjailedPath($source), $this->getUnjailedPath($target));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.fopen.php
-	 *
-	 * @param string $path
-	 * @param string $mode
-	 * @return resource|bool
-	 */
 	public function fopen($path, $mode) {
 		return $this->getWrapperStorage()->fopen($this->getUnjailedPath($path), $mode);
 	}
 
-	/**
-	 * get the mimetype for a file or folder
-	 * The mimetype for a folder is required to be "httpd/unix-directory"
-	 *
-	 * @param string $path
-	 * @return string|bool
-	 */
-	public function getMimeType($path) {
+	public function getMimeType($path): false|string {
 		return $this->getWrapperStorage()->getMimeType($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.hash.php
-	 *
-	 * @param string $type
-	 * @param string $path
-	 * @param bool $raw
-	 * @return string|bool
-	 */
-	public function hash($type, $path, $raw = false) {
+	public function hash($type, $path, $raw = false): false|string {
 		return $this->getWrapperStorage()->hash($type, $this->getUnjailedPath($path), $raw);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.free_space.php
-	 *
-	 * @param string $path
-	 * @return int|float|bool
-	 */
-	public function free_space($path) {
+	public function free_space($path): float|false|int {
 		return $this->getWrapperStorage()->free_space($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.touch.php
-	 * If the backend does not support the operation, false should be returned
-	 *
-	 * @param string $path
-	 * @param int $mtime
-	 * @return bool
-	 */
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		return $this->getWrapperStorage()->touch($this->getUnjailedPath($path), $mtime);
 	}
 
-	/**
-	 * get the path to a local version of the file.
-	 * The local version of the file can be temporary and doesn't have to be persistent across requests
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function getLocalFile($path) {
+	public function getLocalFile($path): false|string {
 		return $this->getWrapperStorage()->getLocalFile($this->getUnjailedPath($path));
 	}
 
-	/**
-	 * check if a file or folder has been updated since $time
-	 *
-	 * @param string $path
-	 * @param int $time
-	 * @return bool
-	 *
-	 * hasUpdated for folders should return at least true if a file inside the folder is add, removed or renamed.
-	 * returning true for other changes in the folder is optional
-	 */
-	public function hasUpdated($path, $time) {
+	public function hasUpdated($path, $time): bool {
 		return $this->getWrapperStorage()->hasUpdated($this->getUnjailedPath($path), $time);
 	}
 
-	public function getCache($path = '', $storage = null) {
+	public function getCache($path = '', $storage = null): ICache {
 		$sourceCache = $this->getWrapperStorage()->getCache($this->getUnjailedPath($path));
 		return new CacheJail($sourceCache, $this->rootPath);
 	}
@@ -367,34 +188,28 @@ public function getOwner($path): string|false {
 		return $this->getWrapperStorage()->getOwner($this->getUnjailedPath($path));
 	}
 
-	public function getWatcher($path = '', $storage = null) {
+	public function getWatcher($path = '', $storage = null): IWatcher {
 		$sourceWatcher = $this->getWrapperStorage()->getWatcher($this->getUnjailedPath($path), $this->getWrapperStorage());
 		return new JailWatcher($sourceWatcher, $this->rootPath);
 	}
 
-	/**
-	 * get the ETag for a file or folder
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function getETag($path) {
+	public function getETag($path): false|string {
 		return $this->getWrapperStorage()->getETag($this->getUnjailedPath($path));
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		return $this->getWrapperStorage()->getMetaData($this->getUnjailedPath($path));
 	}
 
-	public function acquireLock($path, $type, ILockingProvider $provider) {
+	public function acquireLock($path, $type, ILockingProvider $provider): void {
 		$this->getWrapperStorage()->acquireLock($this->getUnjailedPath($path), $type, $provider);
 	}
 
-	public function releaseLock($path, $type, ILockingProvider $provider) {
+	public function releaseLock($path, $type, ILockingProvider $provider): void {
 		$this->getWrapperStorage()->releaseLock($this->getUnjailedPath($path), $type, $provider);
 	}
 
-	public function changeLock($path, $type, ILockingProvider $provider) {
+	public function changeLock($path, $type, ILockingProvider $provider): void {
 		$this->getWrapperStorage()->changeLock($this->getUnjailedPath($path), $type, $provider);
 	}
 
@@ -402,39 +217,26 @@ public function changeLock($path, $type, ILockingProvider $provider) {
 	 * Resolve the path for the source of the share
 	 *
 	 * @param string $path
-	 * @return array
 	 */
-	public function resolvePath($path) {
+	public function resolvePath($path): array {
 		return [$this->getWrapperStorage(), $this->getUnjailedPath($path)];
 	}
 
-	/**
-	 * @param IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @return bool
-	 */
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if ($sourceStorage === $this) {
 			return $this->copy($sourceInternalPath, $targetInternalPath);
 		}
 		return $this->getWrapperStorage()->copyFromStorage($sourceStorage, $sourceInternalPath, $this->getUnjailedPath($targetInternalPath));
 	}
 
-	/**
-	 * @param IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @return bool
-	 */
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if ($sourceStorage === $this) {
 			return $this->rename($sourceInternalPath, $targetInternalPath);
 		}
 		return $this->getWrapperStorage()->moveFromStorage($sourceStorage, $sourceInternalPath, $this->getUnjailedPath($targetInternalPath));
 	}
 
-	public function getPropagator($storage = null) {
+	public function getPropagator($storage = null): IPropagator {
 		if (isset($this->propagator)) {
 			return $this->propagator;
 		}
@@ -460,7 +262,7 @@ public function writeStream(string $path, $stream, ?int $size = null): int {
 		}
 	}
 
-	public function getDirectoryContent($directory): \Traversable {
+	public function getDirectoryContent($directory): \Traversable|false {
 		return $this->getWrapperStorage()->getDirectoryContent($this->getUnjailedPath($directory));
 	}
 }
diff --git a/lib/private/Files/Storage/Wrapper/KnownMtime.php b/lib/private/Files/Storage/Wrapper/KnownMtime.php
index a7360ae134680..d5a3fbc3764d0 100644
--- a/lib/private/Files/Storage/Wrapper/KnownMtime.php
+++ b/lib/private/Files/Storage/Wrapper/KnownMtime.php
@@ -26,7 +26,7 @@ public function __construct($arguments) {
 		$this->clock = $arguments['clock'];
 	}
 
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): float|false|int {
 		$result = parent::file_put_contents($path, $data);
 		if ($result) {
 			$now = $this->clock->now()->getTimestamp();
@@ -35,7 +35,7 @@ public function file_put_contents($path, $data) {
 		return $result;
 	}
 
-	public function stat($path) {
+	public function stat($path): array|false {
 		$stat = parent::stat($path);
 		if ($stat) {
 			$this->applyKnownMtime($path, $stat);
@@ -43,7 +43,7 @@ public function stat($path) {
 		return $stat;
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		$stat = parent::getMetaData($path);
 		if ($stat) {
 			$this->applyKnownMtime($path, $stat);
@@ -51,19 +51,19 @@ public function getMetaData($path) {
 		return $stat;
 	}
 
-	private function applyKnownMtime(string $path, array &$stat) {
+	private function applyKnownMtime(string $path, array &$stat): void {
 		if (isset($stat['mtime'])) {
 			$knownMtime = $this->knowMtimes->get($path) ?? 0;
 			$stat['mtime'] = max($stat['mtime'], $knownMtime);
 		}
 	}
 
-	public function filemtime($path) {
+	public function filemtime($path): false|int {
 		$knownMtime = $this->knowMtimes->get($path) ?? 0;
 		return max(parent::filemtime($path), $knownMtime);
 	}
 
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		$result = parent::mkdir($path);
 		if ($result) {
 			$this->knowMtimes->set($path, $this->clock->now()->getTimestamp());
@@ -71,7 +71,7 @@ public function mkdir($path) {
 		return $result;
 	}
 
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		$result = parent::rmdir($path);
 		if ($result) {
 			$this->knowMtimes->set($path, $this->clock->now()->getTimestamp());
@@ -79,7 +79,7 @@ public function rmdir($path) {
 		return $result;
 	}
 
-	public function unlink($path) {
+	public function unlink($path): bool {
 		$result = parent::unlink($path);
 		if ($result) {
 			$this->knowMtimes->set($path, $this->clock->now()->getTimestamp());
@@ -87,7 +87,7 @@ public function unlink($path) {
 		return $result;
 	}
 
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		$result = parent::rename($source, $target);
 		if ($result) {
 			$this->knowMtimes->set($target, $this->clock->now()->getTimestamp());
@@ -96,7 +96,7 @@ public function rename($source, $target) {
 		return $result;
 	}
 
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		$result = parent::copy($source, $target);
 		if ($result) {
 			$this->knowMtimes->set($target, $this->clock->now()->getTimestamp());
@@ -112,7 +112,7 @@ public function fopen($path, $mode) {
 		return $result;
 	}
 
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		$result = parent::touch($path, $mtime);
 		if ($result) {
 			$this->knowMtimes->set($path, $mtime ?? $this->clock->now()->getTimestamp());
@@ -120,7 +120,7 @@ public function touch($path, $mtime = null) {
 		return $result;
 	}
 
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		$result = parent::copyFromStorage($sourceStorage, $sourceInternalPath, $targetInternalPath);
 		if ($result) {
 			$this->knowMtimes->set($targetInternalPath, $this->clock->now()->getTimestamp());
@@ -128,7 +128,7 @@ public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 		return $result;
 	}
 
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		$result = parent::moveFromStorage($sourceStorage, $sourceInternalPath, $targetInternalPath);
 		if ($result) {
 			$this->knowMtimes->set($targetInternalPath, $this->clock->now()->getTimestamp());
diff --git a/lib/private/Files/Storage/Wrapper/PermissionsMask.php b/lib/private/Files/Storage/Wrapper/PermissionsMask.php
index d6b745c0d3119..0afe7a87415fe 100644
--- a/lib/private/Files/Storage/Wrapper/PermissionsMask.php
+++ b/lib/private/Files/Storage/Wrapper/PermissionsMask.php
@@ -34,31 +34,31 @@ public function __construct($arguments) {
 		$this->mask = $arguments['mask'];
 	}
 
-	private function checkMask($permissions) {
+	private function checkMask($permissions): bool {
 		return ($this->mask & $permissions) === $permissions;
 	}
 
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		return $this->checkMask(Constants::PERMISSION_UPDATE) and parent::isUpdatable($path);
 	}
 
-	public function isCreatable($path) {
+	public function isCreatable($path): bool {
 		return $this->checkMask(Constants::PERMISSION_CREATE) and parent::isCreatable($path);
 	}
 
-	public function isDeletable($path) {
+	public function isDeletable($path): bool {
 		return $this->checkMask(Constants::PERMISSION_DELETE) and parent::isDeletable($path);
 	}
 
-	public function isSharable($path) {
+	public function isSharable($path): bool {
 		return $this->checkMask(Constants::PERMISSION_SHARE) and parent::isSharable($path);
 	}
 
-	public function getPermissions($path) {
+	public function getPermissions($path): int {
 		return $this->storage->getPermissions($path) & $this->mask;
 	}
 
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		//This is a rename of the transfer file to the original file
 		if (dirname($source) === dirname($target) && strpos($source, '.ocTransferId') > 0) {
 			return $this->checkMask(Constants::PERMISSION_CREATE) and parent::rename($source, $target);
@@ -66,28 +66,28 @@ public function rename($source, $target) {
 		return $this->checkMask(Constants::PERMISSION_UPDATE) and parent::rename($source, $target);
 	}
 
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		return $this->checkMask(Constants::PERMISSION_CREATE) and parent::copy($source, $target);
 	}
 
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		$permissions = $this->file_exists($path) ? Constants::PERMISSION_UPDATE : Constants::PERMISSION_CREATE;
 		return $this->checkMask($permissions) and parent::touch($path, $mtime);
 	}
 
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		return $this->checkMask(Constants::PERMISSION_CREATE) and parent::mkdir($path);
 	}
 
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		return $this->checkMask(Constants::PERMISSION_DELETE) and parent::rmdir($path);
 	}
 
-	public function unlink($path) {
+	public function unlink($path): bool {
 		return $this->checkMask(Constants::PERMISSION_DELETE) and parent::unlink($path);
 	}
 
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): float|false|int {
 		$permissions = $this->file_exists($path) ? Constants::PERMISSION_UPDATE : Constants::PERMISSION_CREATE;
 		return $this->checkMask($permissions) ? parent::file_put_contents($path, $data) : false;
 	}
@@ -101,7 +101,7 @@ public function fopen($path, $mode) {
 		}
 	}
 
-	public function getCache($path = '', $storage = null) {
+	public function getCache($path = '', $storage = null): \OCP\Files\Cache\ICache {
 		if (!$storage) {
 			$storage = $this;
 		}
@@ -109,7 +109,7 @@ public function getCache($path = '', $storage = null) {
 		return new CachePermissionsMask($sourceCache, $this->mask);
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		$data = parent::getMetaData($path);
 
 		if ($data && isset($data['permissions'])) {
@@ -119,7 +119,7 @@ public function getMetaData($path) {
 		return $data;
 	}
 
-	public function getScanner($path = '', $storage = null) {
+	public function getScanner($path = '', $storage = null): \OCP\Files\Cache\IScanner {
 		if (!$storage) {
 			$storage = $this->storage;
 		}
diff --git a/lib/private/Files/Storage/Wrapper/Quota.php b/lib/private/Files/Storage/Wrapper/Quota.php
index b642c438266d8..b6cb29d36cea4 100644
--- a/lib/private/Files/Storage/Wrapper/Quota.php
+++ b/lib/private/Files/Storage/Wrapper/Quota.php
@@ -33,9 +33,6 @@ public function __construct($parameters) {
 		$this->quotaIncludeExternalStorage = $parameters['include_external_storage'] ?? false;
 	}
 
-	/**
-	 * @return int|float quota value
-	 */
 	public function getQuota(): int|float {
 		if ($this->quota === null) {
 			$quotaCallback = $this->quotaCallback;
@@ -55,9 +52,8 @@ private function hasQuota(): bool {
 	/**
 	 * @param string $path
 	 * @param IStorage $storage
-	 * @return int|float
 	 */
-	protected function getSize($path, $storage = null) {
+	protected function getSize($path, $storage = null): float|int {
 		if ($this->quotaIncludeExternalStorage) {
 			$rootInfo = Filesystem::getFileInfo('', 'ext');
 			if ($rootInfo) {
@@ -75,13 +71,7 @@ protected function getSize($path, $storage = null) {
 		}
 	}
 
-	/**
-	 * Get free space as limited by the quota
-	 *
-	 * @param string $path
-	 * @return int|float|bool
-	 */
-	public function free_space($path) {
+	public function free_space($path): float|false|int {
 		if (!$this->hasQuota()) {
 			return $this->storage->free_space($path);
 		}
@@ -101,14 +91,7 @@ public function free_space($path) {
 		}
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_put_contents.php
-	 *
-	 * @param string $path
-	 * @param mixed $data
-	 * @return int|float|false
-	 */
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): float|false|int {
 		if (!$this->hasQuota()) {
 			return $this->storage->file_put_contents($path, $data);
 		}
@@ -120,14 +103,7 @@ public function file_put_contents($path, $data) {
 		}
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.copy.php
-	 *
-	 * @param string $source
-	 * @param string $target
-	 * @return bool
-	 */
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		if (!$this->hasQuota()) {
 			return $this->storage->copy($source, $target);
 		}
@@ -139,13 +115,6 @@ public function copy($source, $target) {
 		}
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.fopen.php
-	 *
-	 * @param string $path
-	 * @param string $mode
-	 * @return resource|bool
-	 */
 	public function fopen($path, $mode) {
 		if (!$this->hasQuota()) {
 			return $this->storage->fopen($path, $mode);
@@ -170,10 +139,9 @@ public function fopen($path, $mode) {
 	 * Checks whether the given path is a part file
 	 *
 	 * @param string $path Path that may identify a .part file
-	 * @return bool
 	 * @note this is needed for reusing keys
 	 */
-	private function isPartFile($path) {
+	private function isPartFile($path): bool {
 		$extension = pathinfo($path, PATHINFO_EXTENSION);
 
 		return ($extension === 'part');
@@ -186,13 +154,7 @@ private function shouldApplyQuota(string $path): bool {
 		return str_starts_with(ltrim($path, '/'), 'files/');
 	}
 
-	/**
-	 * @param IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @return bool
-	 */
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if (!$this->hasQuota()) {
 			return $this->storage->copyFromStorage($sourceStorage, $sourceInternalPath, $targetInternalPath);
 		}
@@ -204,13 +166,7 @@ public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 		}
 	}
 
-	/**
-	 * @param IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @return bool
-	 */
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if (!$this->hasQuota()) {
 			return $this->storage->moveFromStorage($sourceStorage, $sourceInternalPath, $targetInternalPath);
 		}
@@ -222,7 +178,7 @@ public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 		}
 	}
 
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		if (!$this->hasQuota()) {
 			return $this->storage->mkdir($path);
 		}
@@ -234,7 +190,7 @@ public function mkdir($path) {
 		return parent::mkdir($path);
 	}
 
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		if (!$this->hasQuota()) {
 			return $this->storage->touch($path, $mtime);
 		}
diff --git a/lib/private/Files/Storage/Wrapper/Wrapper.php b/lib/private/Files/Storage/Wrapper/Wrapper.php
index 93dcacdfb42f0..a387609c0ec61 100644
--- a/lib/private/Files/Storage/Wrapper/Wrapper.php
+++ b/lib/private/Files/Storage/Wrapper/Wrapper.php
@@ -8,7 +8,12 @@
 namespace OC\Files\Storage\Wrapper;
 
 use OC\Files\Storage\FailedStorage;
-use OCP\Files\InvalidPathException;
+use OC\Files\Storage\Storage;
+use OCP\Files\Cache\ICache;
+use OCP\Files\Cache\IPropagator;
+use OCP\Files\Cache\IScanner;
+use OCP\Files\Cache\IUpdater;
+use OCP\Files\Cache\IWatcher;
 use OCP\Files\Storage\ILockingStorage;
 use OCP\Files\Storage\IStorage;
 use OCP\Files\Storage\IWriteStreamStorage;
@@ -35,10 +40,7 @@ public function __construct($parameters) {
 		$this->storage = $parameters['storage'];
 	}
 
-	/**
-	 * @return \OC\Files\Storage\Storage
-	 */
-	public function getWrapperStorage() {
+	public function getWrapperStorage(): Storage {
 		if (!$this->storage) {
 			$message = 'storage wrapper ' . get_class($this) . " doesn't have a wrapped storage set";
 			$logger = Server::get(LoggerInterface::class);
@@ -48,319 +50,130 @@ public function getWrapperStorage() {
 		return $this->storage;
 	}
 
-	/**
-	 * Get the identifier for the storage,
-	 * the returned id should be the same for every storage object that is created with the same parameters
-	 * and two storage objects with the same id should refer to two storages that display the same files.
-	 *
-	 * @return string
-	 */
-	public function getId() {
+	public function getId(): string {
 		return $this->getWrapperStorage()->getId();
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.mkdir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function mkdir($path) {
+	public function mkdir($path): bool {
 		return $this->getWrapperStorage()->mkdir($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.rmdir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function rmdir($path) {
+	public function rmdir($path): bool {
 		return $this->getWrapperStorage()->rmdir($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.opendir.php
-	 *
-	 * @param string $path
-	 * @return resource|false
-	 */
 	public function opendir($path) {
 		return $this->getWrapperStorage()->opendir($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.is_dir.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function is_dir($path) {
+	public function is_dir($path): bool {
 		return $this->getWrapperStorage()->is_dir($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.is_file.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function is_file($path) {
+	public function is_file($path): bool {
 		return $this->getWrapperStorage()->is_file($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.stat.php
-	 * only the following keys are required in the result: size and mtime
-	 *
-	 * @param string $path
-	 * @return array|bool
-	 */
-	public function stat($path) {
+	public function stat($path): array|false {
 		return $this->getWrapperStorage()->stat($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filetype.php
-	 *
-	 * @param string $path
-	 * @return string|bool
-	 */
-	public function filetype($path) {
+	public function filetype($path): string|false {
 		return $this->getWrapperStorage()->filetype($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filesize.php
-	 * The result for filesize when called on a folder is required to be 0
-	 */
 	public function filesize($path): false|int|float {
 		return $this->getWrapperStorage()->filesize($path);
 	}
 
-	/**
-	 * check if a file can be created in $path
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isCreatable($path) {
+	public function isCreatable($path): bool {
 		return $this->getWrapperStorage()->isCreatable($path);
 	}
 
-	/**
-	 * check if a file can be read
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isReadable($path) {
+	public function isReadable($path): bool {
 		return $this->getWrapperStorage()->isReadable($path);
 	}
 
-	/**
-	 * check if a file can be written to
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		return $this->getWrapperStorage()->isUpdatable($path);
 	}
 
-	/**
-	 * check if a file can be deleted
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isDeletable($path) {
+	public function isDeletable($path): bool {
 		return $this->getWrapperStorage()->isDeletable($path);
 	}
 
-	/**
-	 * check if a file can be shared
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function isSharable($path) {
+	public function isSharable($path): bool {
 		return $this->getWrapperStorage()->isSharable($path);
 	}
 
-	/**
-	 * get the full permissions of a path.
-	 * Should return a combination of the PERMISSION_ constants defined in lib/public/constants.php
-	 *
-	 * @param string $path
-	 * @return int
-	 */
-	public function getPermissions($path) {
+	public function getPermissions($path): int {
 		return $this->getWrapperStorage()->getPermissions($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_exists.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function file_exists($path) {
+	public function file_exists($path): bool {
 		return $this->getWrapperStorage()->file_exists($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.filemtime.php
-	 *
-	 * @param string $path
-	 * @return int|bool
-	 */
-	public function filemtime($path) {
+	public function filemtime($path): int|false {
 		return $this->getWrapperStorage()->filemtime($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_get_contents.php
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function file_get_contents($path) {
+	public function file_get_contents($path): string|false {
 		return $this->getWrapperStorage()->file_get_contents($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.file_put_contents.php
-	 *
-	 * @param string $path
-	 * @param mixed $data
-	 * @return int|float|false
-	 */
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): int|float|false {
 		return $this->getWrapperStorage()->file_put_contents($path, $data);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.unlink.php
-	 *
-	 * @param string $path
-	 * @return bool
-	 */
-	public function unlink($path) {
+	public function unlink($path): bool {
 		return $this->getWrapperStorage()->unlink($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.rename.php
-	 *
-	 * @param string $source
-	 * @param string $target
-	 * @return bool
-	 */
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		return $this->getWrapperStorage()->rename($source, $target);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.copy.php
-	 *
-	 * @param string $source
-	 * @param string $target
-	 * @return bool
-	 */
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		return $this->getWrapperStorage()->copy($source, $target);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.fopen.php
-	 *
-	 * @param string $path
-	 * @param string $mode
-	 * @return resource|bool
-	 */
 	public function fopen($path, $mode) {
 		return $this->getWrapperStorage()->fopen($path, $mode);
 	}
 
-	/**
-	 * get the mimetype for a file or folder
-	 * The mimetype for a folder is required to be "httpd/unix-directory"
-	 *
-	 * @param string $path
-	 * @return string|bool
-	 */
-	public function getMimeType($path) {
+	public function getMimeType($path): string|false {
 		return $this->getWrapperStorage()->getMimeType($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.hash.php
-	 *
-	 * @param string $type
-	 * @param string $path
-	 * @param bool $raw
-	 * @return string|bool
-	 */
-	public function hash($type, $path, $raw = false) {
+	public function hash($type, $path, $raw = false): string|false {
 		return $this->getWrapperStorage()->hash($type, $path, $raw);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.free_space.php
-	 *
-	 * @param string $path
-	 * @return int|float|bool
-	 */
-	public function free_space($path) {
+	public function free_space($path): int|float|false {
 		return $this->getWrapperStorage()->free_space($path);
 	}
 
-	/**
-	 * see https://www.php.net/manual/en/function.touch.php
-	 * If the backend does not support the operation, false should be returned
-	 *
-	 * @param string $path
-	 * @param int $mtime
-	 * @return bool
-	 */
-	public function touch($path, $mtime = null) {
+	public function touch($path, $mtime = null): bool {
 		return $this->getWrapperStorage()->touch($path, $mtime);
 	}
 
-	/**
-	 * get the path to a local version of the file.
-	 * The local version of the file can be temporary and doesn't have to be persistent across requests
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function getLocalFile($path) {
+	public function getLocalFile($path): string|false {
 		return $this->getWrapperStorage()->getLocalFile($path);
 	}
 
-	/**
-	 * check if a file or folder has been updated since $time
-	 *
-	 * @param string $path
-	 * @param int $time
-	 * @return bool
-	 *
-	 * hasUpdated for folders should return at least true if a file inside the folder is add, removed or renamed.
-	 * returning true for other changes in the folder is optional
-	 */
-	public function hasUpdated($path, $time) {
+	public function hasUpdated($path, $time): bool {
 		return $this->getWrapperStorage()->hasUpdated($path, $time);
 	}
 
-	public function getCache($path = '', $storage = null) {
+	public function getCache($path = '', $storage = null): ICache {
 		if (!$storage) {
 			$storage = $this;
 		}
 		return $this->getWrapperStorage()->getCache($path, $storage);
 	}
 
-	public function getScanner($path = '', $storage = null) {
+	public function getScanner($path = '', $storage = null): IScanner {
 		if (!$storage) {
 			$storage = $this;
 		}
@@ -371,66 +184,44 @@ public function getOwner($path): string|false {
 		return $this->getWrapperStorage()->getOwner($path);
 	}
 
-	public function getWatcher($path = '', $storage = null) {
+	public function getWatcher($path = '', $storage = null): IWatcher {
 		if (!$storage) {
 			$storage = $this;
 		}
 		return $this->getWrapperStorage()->getWatcher($path, $storage);
 	}
 
-	public function getPropagator($storage = null) {
+	public function getPropagator($storage = null): IPropagator {
 		if (!$storage) {
 			$storage = $this;
 		}
 		return $this->getWrapperStorage()->getPropagator($storage);
 	}
 
-	public function getUpdater($storage = null) {
+	public function getUpdater($storage = null): IUpdater {
 		if (!$storage) {
 			$storage = $this;
 		}
 		return $this->getWrapperStorage()->getUpdater($storage);
 	}
 
-	public function getStorageCache() {
+	public function getStorageCache(): \OC\Files\Cache\Storage {
 		return $this->getWrapperStorage()->getStorageCache();
 	}
 
-	/**
-	 * get the ETag for a file or folder
-	 *
-	 * @param string $path
-	 * @return string|false
-	 */
-	public function getETag($path) {
+	public function getETag($path): string|false {
 		return $this->getWrapperStorage()->getETag($path);
 	}
 
-	/**
-	 * Returns true
-	 *
-	 * @return true
-	 */
-	public function test() {
+	public function test(): bool {
 		return $this->getWrapperStorage()->test();
 	}
 
-	/**
-	 * Returns the wrapped storage's value for isLocal()
-	 *
-	 * @return bool wrapped storage's isLocal() value
-	 */
-	public function isLocal() {
+	public function isLocal(): bool {
 		return $this->getWrapperStorage()->isLocal();
 	}
 
-	/**
-	 * Check if the storage is an instance of $class or is a wrapper for a storage that is an instance of $class
-	 *
-	 * @param class-string<IStorage> $class
-	 * @return bool
-	 */
-	public function instanceOfStorage($class) {
+	public function instanceOfStorage($class): bool {
 		if (ltrim($class, '\\') === 'OC\Files\Storage\Shared') {
 			// FIXME Temporary fix to keep existing checks working
 			$class = '\OCA\Files_Sharing\SharedStorage';
@@ -443,7 +234,7 @@ public function instanceOfStorage($class) {
 	 * @psalm-param class-string<T> $class
 	 * @psalm-return T|null
 	 */
-	public function getInstanceOfStorage(string $class) {
+	public function getInstanceOfStorage(string $class): ?IStorage {
 		$storage = $this;
 		while ($storage instanceof Wrapper) {
 			if ($storage instanceof $class) {
@@ -468,53 +259,23 @@ public function __call($method, $args) {
 		return call_user_func_array([$this->getWrapperStorage(), $method], $args);
 	}
 
-	/**
-	 * A custom storage implementation can return an url for direct download of a give file.
-	 *
-	 * For now the returned array can hold the parameter url - in future more attributes might follow.
-	 *
-	 * @param string $path
-	 * @return array|bool
-	 */
-	public function getDirectDownload($path) {
+	public function getDirectDownload($path): array|false {
 		return $this->getWrapperStorage()->getDirectDownload($path);
 	}
 
-	/**
-	 * Get availability of the storage
-	 *
-	 * @return array [ available, last_checked ]
-	 */
-	public function getAvailability() {
+	public function getAvailability(): array {
 		return $this->getWrapperStorage()->getAvailability();
 	}
 
-	/**
-	 * Set availability of the storage
-	 *
-	 * @param bool $isAvailable
-	 */
-	public function setAvailability($isAvailable) {
+	public function setAvailability($isAvailable): void {
 		$this->getWrapperStorage()->setAvailability($isAvailable);
 	}
 
-	/**
-	 * @param string $path the path of the target folder
-	 * @param string $fileName the name of the file itself
-	 * @return void
-	 * @throws InvalidPathException
-	 */
-	public function verifyPath($path, $fileName) {
+	public function verifyPath($path, $fileName): void {
 		$this->getWrapperStorage()->verifyPath($path, $fileName);
 	}
 
-	/**
-	 * @param IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @return bool
-	 */
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if ($sourceStorage === $this) {
 			return $this->copy($sourceInternalPath, $targetInternalPath);
 		}
@@ -522,13 +283,7 @@ public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 		return $this->getWrapperStorage()->copyFromStorage($sourceStorage, $sourceInternalPath, $targetInternalPath);
 	}
 
-	/**
-	 * @param IStorage $sourceStorage
-	 * @param string $sourceInternalPath
-	 * @param string $targetInternalPath
-	 * @return bool
-	 */
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		if ($sourceStorage === $this) {
 			return $this->rename($sourceInternalPath, $targetInternalPath);
 		}
@@ -536,32 +291,29 @@ public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $t
 		return $this->getWrapperStorage()->moveFromStorage($sourceStorage, $sourceInternalPath, $targetInternalPath);
 	}
 
-	public function getMetaData($path) {
+	public function getMetaData($path): ?array {
 		return $this->getWrapperStorage()->getMetaData($path);
 	}
 
-	public function acquireLock($path, $type, ILockingProvider $provider) {
+	public function acquireLock($path, $type, ILockingProvider $provider): void {
 		if ($this->getWrapperStorage()->instanceOfStorage('\OCP\Files\Storage\ILockingStorage')) {
 			$this->getWrapperStorage()->acquireLock($path, $type, $provider);
 		}
 	}
 
-	public function releaseLock($path, $type, ILockingProvider $provider) {
+	public function releaseLock($path, $type, ILockingProvider $provider): void {
 		if ($this->getWrapperStorage()->instanceOfStorage('\OCP\Files\Storage\ILockingStorage')) {
 			$this->getWrapperStorage()->releaseLock($path, $type, $provider);
 		}
 	}
 
-	public function changeLock($path, $type, ILockingProvider $provider) {
+	public function changeLock($path, $type, ILockingProvider $provider): void {
 		if ($this->getWrapperStorage()->instanceOfStorage('\OCP\Files\Storage\ILockingStorage')) {
 			$this->getWrapperStorage()->changeLock($path, $type, $provider);
 		}
 	}
 
-	/**
-	 * @return bool
-	 */
-	public function needsPartFile() {
+	public function needsPartFile(): bool {
 		return $this->getWrapperStorage()->needsPartFile();
 	}
 
@@ -579,11 +331,11 @@ public function writeStream(string $path, $stream, ?int $size = null): int {
 		}
 	}
 
-	public function getDirectoryContent($directory): \Traversable {
+	public function getDirectoryContent($directory): \Traversable|false {
 		return $this->getWrapperStorage()->getDirectoryContent($directory);
 	}
 
-	public function isWrapperOf(IStorage $storage) {
+	public function isWrapperOf(IStorage $storage): bool {
 		$wrapped = $this->getWrapperStorage();
 		if ($wrapped === $storage) {
 			return true;
diff --git a/lib/private/Files/Stream/Quota.php b/lib/private/Files/Stream/Quota.php
index d8e7ae6dff08f..cc737910fd8dc 100644
--- a/lib/private/Files/Stream/Quota.php
+++ b/lib/private/Files/Stream/Quota.php
@@ -23,7 +23,7 @@ class Quota extends Wrapper {
 	/**
 	 * @param resource $stream
 	 * @param int $limit
-	 * @return bool|resource
+	 * @return resource|false
 	 */
 	public static function wrap($stream, $limit) {
 		$context = stream_context_create([
diff --git a/lib/private/Files/Utils/Scanner.php b/lib/private/Files/Utils/Scanner.php
index bcc54dea0dcb1..40201d10b9925 100644
--- a/lib/private/Files/Utils/Scanner.php
+++ b/lib/private/Files/Utils/Scanner.php
@@ -106,6 +106,7 @@ protected function getMounts($dir) {
 	 * @param \OC\Files\Mount\MountPoint $mount
 	 */
 	protected function attachListener($mount) {
+		/** @var \OC\Files\Cache\Scanner $scanner */
 		$scanner = $mount->getStorage()->getScanner();
 		$scanner->listen('\OC\Files\Cache\Scanner', 'scanFile', function ($path) use ($mount) {
 			$this->emit('\OC\Files\Utils\Scanner', 'scanFile', [$mount->getMountPoint() . $path]);
@@ -145,6 +146,7 @@ public function backgroundScan($dir) {
 					continue;
 				}
 
+				/** @var \OC\Files\Cache\Scanner $scanner */
 				$scanner = $storage->getScanner();
 				$this->attachListener($mount);
 
@@ -221,6 +223,7 @@ public function scan($dir = '', $recursive = \OC\Files\Cache\Scanner::SCAN_RECUR
 				continue;
 			}
 			$relativePath = $mount->getInternalPath($dir);
+			/** @var \OC\Files\Cache\Scanner $scanner */
 			$scanner = $storage->getScanner();
 			$scanner->setUseTransactions(false);
 			$this->attachListener($mount);
diff --git a/lib/private/Lockdown/Filesystem/NullStorage.php b/lib/private/Lockdown/Filesystem/NullStorage.php
index 00124877e9d59..242ffe5bec87a 100644
--- a/lib/private/Lockdown/Filesystem/NullStorage.php
+++ b/lib/private/Lockdown/Filesystem/NullStorage.php
@@ -8,6 +8,7 @@
 use Icewind\Streams\IteratorDirectory;
 use OC\Files\FileInfo;
 use OC\Files\Storage\Common;
+use OCP\Files\Cache\ICache;
 use OCP\Files\Storage\IStorage;
 
 class NullStorage extends Common {
@@ -31,15 +32,15 @@ public function opendir($path) {
 		return new IteratorDirectory([]);
 	}
 
-	public function is_dir($path) {
+	public function is_dir($path): bool {
 		return $path === '';
 	}
 
-	public function is_file($path) {
+	public function is_file($path): bool {
 		return false;
 	}
 
-	public function stat($path) {
+	public function stat($path): never {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
@@ -51,43 +52,43 @@ public function filesize($path): false|int|float {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function isCreatable($path) {
+	public function isCreatable($path): bool {
 		return false;
 	}
 
-	public function isReadable($path) {
+	public function isReadable($path): bool {
 		return $path === '';
 	}
 
-	public function isUpdatable($path) {
+	public function isUpdatable($path): bool {
 		return false;
 	}
 
-	public function isDeletable($path) {
+	public function isDeletable($path): bool {
 		return false;
 	}
 
-	public function isSharable($path) {
+	public function isSharable($path): bool {
 		return false;
 	}
 
-	public function getPermissions($path) {
-		return null;
+	public function getPermissions($path): int {
+		return 0;
 	}
 
 	public function file_exists($path) {
 		return $path === '';
 	}
 
-	public function filemtime($path) {
+	public function filemtime($path): false|int {
 		return ($path === '') ? time() : false;
 	}
 
-	public function file_get_contents($path) {
+	public function file_get_contents($path): bool|string {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function file_put_contents($path, $data) {
+	public function file_put_contents($path, $data): float|bool|int {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
@@ -95,11 +96,11 @@ public function unlink($path) {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function rename($source, $target) {
+	public function rename($source, $target): bool {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function copy($source, $target) {
+	public function copy($source, $target): bool {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
@@ -107,15 +108,15 @@ public function fopen($path, $mode) {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function getMimeType($path) {
+	public function getMimeType($path): bool|string {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function hash($type, $path, $raw = false) {
+	public function hash($type, $path, $raw = false): bool|string {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function free_space($path) {
+	public function free_space($path): float|bool|int {
 		return FileInfo::SPACE_UNKNOWN;
 	}
 
@@ -123,35 +124,35 @@ public function touch($path, $mtime = null) {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function getLocalFile($path) {
+	public function getLocalFile($path): bool|string {
 		return false;
 	}
 
-	public function hasUpdated($path, $time) {
+	public function hasUpdated($path, $time): bool {
 		return false;
 	}
 
-	public function getETag($path) {
+	public function getETag($path): bool|string {
 		return '';
 	}
 
-	public function isLocal() {
+	public function isLocal(): bool {
 		return false;
 	}
 
-	public function getDirectDownload($path) {
+	public function getDirectDownload($path): bool|array {
 		return false;
 	}
 
-	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = false) {
+	public function copyFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath, $preserveMtime = false): bool {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath) {
+	public function moveFromStorage(IStorage $sourceStorage, $sourceInternalPath, $targetInternalPath): bool {
 		throw new \OC\ForbiddenException('This request is not allowed to access the filesystem');
 	}
 
-	public function test() {
+	public function test(): bool {
 		return true;
 	}
 
@@ -159,7 +160,7 @@ public function getOwner($path): string|false {
 		return false;
 	}
 
-	public function getCache($path = '', $storage = null) {
+	public function getCache($path = '', $storage = null): ICache {
 		return new NullCache();
 	}
 }