Library documentation
The Library
service is responsible for the management of system-managed and custom collections of resources also known as playlists.
System Playlists
There are currently two playlists that are automatically created for all users and that cannot be modified or deleted by the user itself. Such playlists are the collection of resources liked by the user, the Liked
playlist, and the collection of resources that has been marked for future consumption (e.g. watchlist or watch later), the Later
playlist.