Many tripod quick release plates have a plastic or metal peg near the screw. You can press down on the peg, and then when you release it, it pops back up. I've looked at photos of many camera bottoms, and I haven't seen any camera that has a hole that the peg would fit into. What is the purpose of this peg?
I just got a smartphone tripod adapter, and this adapter has some concave areas on the bottom part that sits flush against the quick release plate. As I was screwing the adapter onto my tripod's quick release plate, the peg on the plate got caught in one of the concave areas and then got ripped out of the plate. I'd like to know the purpose of this peg before deciding if I can get rid of it.