Is there some way to de-compile Godot projects? I wouldn't be surprised if there was, but I'm interested to know how you got into the game files lol. It's no problem though. I can't remember for sure, but some of those music files might be from the original version, and some were just used for the trailer. There might also be some other placeholder music, art, etc. in the project that isn't mine but I forget if I deleted those before releasing.
I hadn't thought about releasing the variations of the day theme. I think there's the guitar-only version which is used in-game (I think? It's been a while lol), and the guitar, piano, percussion version which is used in the trailer. If you already have the files though you're welcome to use them yourself!