If you uninstall an app ? Does it remove ALL files associated?

This is a generic question about the nextcloud apps.
If you uninstall an app, does it remove ALL files associated ?
OR is each app different ?

I want to disable / remove the bookmarks app then add it back again.
Will the bookmarks folders also be removed or will they return if I reinstall the app ?

Please advise.

I would recommend to reach out directly to the devs of this app (maybe create an issue on Github).