The extension can run in either client or server side.
When running on the client side (ui), only the data on the client (extensions, UI, ...) will be synchronized.
When running on the server side (workspace), only the extensions available on the remote server will be synchronized.
It's recommanded to use a new profile for the server side (for example: profile: remote).
remote.extensionKind
remote.extensionKind: https://code.visualstudio.com/api/advanced-topics/remote-extensions#common-problemsremote.SSH.defaultExtensions: https://code.visualstudio.com/docs/remote/ssh#_always-installed-extensions