RhythmBox MQTT Plugin
This is a plugin for Rhythmbox that will post the current title/album/artist to MQTT as well as the current playing status (playing/paused/inactive).
It was developed for a particular use case of mine, namely this LED status screen:
I tried looking for a Rhythmbox MQTT plugin but didn't find one. Maybe that means nobody else needs such a thing. But just in case it's useful to anyone else, you can find the source code on Codeberg. It has not been tested beyond in my own use on my own desktop, so it is likely to be buggy.