I decided to try building a datapack with a program from another branch and noticed a few issues:

• Instead of three functions (corresponding to three songs) in jukebox_song, only one was created.

• In the function, there's a reference to infinite_music_discs:music_disc.(song name), which shouldn't be there because sounds in Minecraft are defined without the resourcepack name. Indeed, after removing it, the sound appeared and the music worked correctly.

I applaud your enthusiasm but that's a dev branch so yeah it might not work yet. Commit c011fd resolves some of your issues.

FYI Minecraft sounds can be defined in namespaces other than the default minecraft namespace, the IMD resourcepack just doesn't do that right now. I want to update the resourcepack to put custom discs in their own namespace so you can have multiple packs without collisions between sounds.json etc

Thanks for the help! Good luck with the rest of the development.