Is all the info here correct? Are there other songs I should make covers of for players to learn in the game? Or instruments that would be fun to play? This is the "Learned Songs" menu. Just another way to add collectibles and fun activities to the game.
The actual original copyrighted sound files won't be included in the build, but people will be able to drop their own music into the Resources folder for the game to use. The game will eventually include custom covers of these songs by me. The idea is that you can either listen to music you've learned in the menus or world, or play it on the instrument you have selected, in the game world.
Here's the original fb UDIC post.