It's a poor attempt at a captive nut. A nut is welded to a square of flat steel. This sits in a square recess. The idea is, it won't spin. The reality - the steel square is undersized, the plastic is soft, it spins. You can often jam a screwdriver into the gap to stop it so you can wind the screw out. Every glee owner who's ever had the front guard off has found this abomination, others will be along shortly with their cunning work-rounds. "You are not alone. "