If you are using user made “One Press” songs, OPB, DOP, OPBk, etc., on some songs the entire song is in the intro, and one press of the pedal starts it playing. The song then goes into a “null” or “empty” main loop, and you double tap to end. There is no outro. Other songs have the entire song in the outro section. On those songs, when you single tap to play, the song loops in a null loop util you double tap, then the entire song plays through and ends by itself. One additional type that is used sometimes, may or may not have an intro section, but then the main body of the song is in a main loop. These play through, and there is dead time at the end of the main loop, where you can have time to double tap and end the song. These also have nothing in the outro.
Of course, users are making to make songs as it suits them, so so users may may song from time to time with nothing in the outro. You can see the song structure when you load the song into BB Manager. It’s always a good idea to take a look at the song before you play it. Or better yet, try it out with the built-in virtual pedal and you can see how it works.