I’m no expert here so others should feel free to chime in here. From what I know, it is steaming but some here will say that once you put some liquid in the foil, it’s called braising. What ever. Yeah, it helps to put something in the pouch and I think that a tighter wrap vs. a loose foil helps. Apple juice is a good choice, I think, but I know a guy from Canada that used to drizzle honey on his (meat side) then sprinkle with brown sugar, turn them meat side down in the foil and wrap tightly. Individually. Of course, everyone removes from the foil near the end to firm them back up. He did very well in comps with this method.
Spraying with apple juice is just that. Ribs are not in the foil. There’s a saying, “If you’re looking, you’re not cooking” and that applies here. It takes time for any type of pit to recover after opening. Some do this religiously, others, myself included, don’t. I might near the end if, while I’m checking for doneness, find that the ribs are looking on the dry side though. You’ll find, during your searches, a 3-2-1 method. This is used loosely but means, 3 hours in the smoke, 2 hours in foil, and 1 hour back on the grate to firm up. Most will say they won’t go 2 hours as it makes them too mushy. Also, this is for spares, not loin backs.
Bill