ext_localconf.php

<?php
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3\CMS\Core\Information\Typo3Version;
use TYPO3\CMS\Core\Utility\ExtensionManagementUtility;

defined('TYPO3') || die('Access denied.');

(function () {
    if (empty($GLOBALS['TYPO3_CONF_VARS']['RTE']['Presets']['microtemplate'])) {
        $versionInformation = GeneralUtility::makeInstance(Typo3Version::class);
        if ($versionInformation->getMajorVersion() >= 12) {
            $GLOBALS['TYPO3_CONF_VARS']['RTE']['Presets']['microtemplate'] = 'EXT:microtemplate/Configuration/RTE/Microtemplate.yaml';
        } else {
            $GLOBALS['TYPO3_CONF_VARS']['RTE']['Presets']['microtemplate'] = 'EXT:microtemplate/Configuration/RTE/Microtemplate_11LTS.yaml';
        }
    }

    # Check if ext:personnel is loaded and add TS constant
    if (ExtensionManagementUtility::isLoaded('personnel')) {
        ExtensionManagementUtility::addTypoScriptConstants('
            microtemplate.personnelIsLoaded = 1
        ');
    } else {
        ExtensionManagementUtility::addTypoScriptConstants('
            microtemplate.personnelIsLoaded = 0
        ');
    }
    if (ExtensionManagementUtility::isLoaded('pagelist')) {
        ExtensionManagementUtility::addTypoScriptConstants('
            microtemplate.pagelistIsLoaded = 1
        ');
    } else {
        ExtensionManagementUtility::addTypoScriptConstants('
            microtemplate.pagelistIsLoaded = 0
        ');
    }
})();