I learned a bit about these "screws" having similar issues on my 2012 Elantra. The OEM part is 86590-28000 , and is called a Fender Liner Clip. They are used in many places around the car, including the rear trunk liner, in the engine compartment, and of course, to hold the fender liner in place.In order to replace back light bulbs, one needs to remove the roof liner. The "screws" all seem loose to start with. How does one remove the screws without damaging them? Thank you.