[MultipleParadox]

Hi
In an attempt to strip the paint of my Hicapa frame (4.3) I discovered a "new" small part I wasn't aware of... (New for me, that is)

Long story short, there's a very small plastic insert held by a tiny screw on the opposite site of the safety on the frame; anyone can shed light on what this is?
It kinda melted away on contact with the paint stripper (which to my dismay was of no good stripping the paint on the frame, but that's a different story :P)

Thanks

I can post photos if no one can figure out what I mean