My wife asked me this question, which sent me on a mission:
“In the Sonos app when I ‘heart’ a song on Spotify, where does it go?”
The tooltip for the Heart icon says “Save to Your Music” - this is a total lie.
Hearted songs in fact show up here:
- In the Sonos app they are under Spotify / Your Library / Songs
- In the Spotify web player they are under Liked Songs, which is a playlist
- In the Spotify iOS app they are under Your Library / Liked Songs