Debriefing can happen through exit slips, though students need to take their reflective thoughts home with them too. Debriefing can happen through conversation, in pairs, in small groups, as a whole class. Debriefing can happen with sticky notes - one teacher decided he'd have students slap an ah-ha! sticky note on the wall by his door as they walked out each day.
However it happens, the practice can't be shortchanged. It's so tempting to plan from the bell, build in the bellringer and roll from there right through clean-up. But the best way to let students really understand what they've learned each day is to stop with a small handful of minutes left and give them space to reflect. It's probably helpful to lead into this by reinforcing the day's learning target, to remind students of the purpose behind the workshop or the lab or the classwork they've just been involved in. And it's not cheating to ask students leading questions, like "what one thing did you learn today?" or "what are you going to tell your parents you learned in class today?". Because lots of students will walk out, having been plenty busy, perfectly studious, but without a clear sense of what they learned and how that learning connects to what they already know and what they want to know.
And that will leave teachers without a clear enough sense - without a formative sense - of what they need to teach, or re-teach, tomorrow.