Please see the top level Contribution Guide for the project setup and all development flows.
This package is an LSP Server and uses The VS Code Language Server library to implement the Language Server Protocol.
To start the language server, first you must start the VS Code extension that runs it by launching the Launch Client configuration in the launch.json file from VS Code. This will open a new instance of VS Code that can be used for debugging.
After the server is started, attach the debugger to the process by launching the Attach to Server configuration in the same launch.json file.
See the vscode-ui5-language-assistant contribution guide for how to see the messages passed between the VS Code extension and the LSP server.