+STARTUP_SONG // plays when the keyboard starts up (audio.c)
+GOODBYE_SONG // plays when you press the RESET key (quantum.c)
+AG_NORM_SONG // plays when you press AG_NORM (quantum.c)
+AG_SWAP_SONG // plays when you press AG_SWAP (quantum.c)
+MUSIC_ON_SONG // plays when music mode is activated (process_music.c)
+MUSIC_OFF_SONG // plays when music mode is deactivated (process_music.c)