Two new things in the library.
On Repeat is a playlist of the 20 songs you have played most in the last 30 days, re-ranking itself as you listen. It is built from local play counts, so there is no YouTube playlist behind it and it works signed out. It appears in your library once there is anything in it, and puts itself on the home Shortcuts grid at 5 songs (remove it and it stays removed).
The library page now shows albums and artists. It only ever fetched playlists before, so saved albums did not appear and artists were missing entirely. There are now tabs for All, Playlists, Albums and Artists.
Album pages get a Save to library button next to Play and Shuffle, which is what fills the Albums tab in the first place. There was previously no way to add an album to your library from the app at all.