A wee bit dusty under that hood eh?
No questions will be answered till you clean that up and post a new photo!
Ok, just kidding. Looks like a missing plastic rivet no?

 

haha yes I tried a bit but still needs some more love. Just finished with PS flush (still troubleshooting noise) and next will be general cleanup and rust fix on the sides. Previous owner never spent a penny on it for 15 years of ownership 😮‍💨 and was parked out in the Canadian winter. Think I might need to change control arm but my mechanic said no, strange he said don’t change anything it will cause knock on issues 😅

yes one rivet is missing but almost seems there may have been a plastic panel holding it all in place as you see the shade is a tad bit lighter on the insulation and dropping from the sides too

 

Don't think there is something missing, but I remember Mercedes did a revision of it with some heat reflection part which doesn't bend down.