in the \game\music folder you will find all the mp3/ogg files. Since, unfortunately, I didn't know what I was doing when I started the game, not everything is documented in Season 1 (v.0.12 is the last update of Season 1), but most files have a link with the same name to where that song was downloaded.
In Season 2, in the same folder, you can find an Excel with the documentation about the music.