What part is this and where does it go?

hey guys- took off the back cover to work on fixing my trackpad- and this little part fell out and I don’t know where it’s supposed to go! i fixed my trackpad, but thought id try to put this unknown part back in before reassembling the cover. it looks like a little tiny “button” (like on a coat) with four holes in the center of it.

here's a close up pic of the "button". I don't think it has anything to do with the cover or the feet. i put the screwdriver in the photo for scale.