2004 Ford mustang driver side window
 

I was rolling Window and heard something buckle.. Took door panel off and saw this on bottom of door.. I'm assuming it attaches to glass.. What's the name of the part.. What's it do? And is it needed? TIA

Attachment 201829

https://cimg9.ibsrv.net/gimg/themust...0583fec35.jpeg<br >

That appears to be a glass guide bracket. I think the white plastic section slides on the steel track to keep the window aligned.