Edit: ^^^This^^^
It's technically a dust deflector; purpose is to direct some air
down and over the rear window to keep it a bit cleaner. It also blows
some of the water off the window when it's raining, so you don't have to
use the rear wiper continuously.
To remove it there are two screws on either end of the deflector/wing,
remove them first. Then you'll see two exposed screws on each mounting
bracket. There is a thrid screw inside the bracket, might need a bright flashlight to see it. You may find water inside that bracket hiding the screws.
So five screws on each side to remove the deflector/wing and brackets.
There will be three nutserts on each side, you can leave those in place
and reinstall the three screws that held the bracket in place. If you remove
the nutserts you'll then have to fill in the holes, sand, prime, paint.
WARNING: IME the mounting bracket screws (if you reinstall them to plug the nutsets) MUST be sealed (I used Permatex thread sealer when I had the wing off to repair rust) otherwise water can get into the rear hatch by working it's way past the threads of the screws.
Personally I like how the deflector keeps the rear window cleaner and blows
some rain drops off so I don't have to use the rear wiper continuously
when it's raining outside. The nutserts for the brackets however tend to be rust magnets.
This, IMHO, is because the area below the brackets is occupied by a thin sheet of foam that holds water and keeps that area wet around the nutserts. Also because the nutserts were punched through the factory paint/sheet metal which makes it more likely it will rust.
When I fixed the rust under the brackets on my 96 80 I did not replace that thin foam sheet, leaving that ~1/16" space between the bottom of the bracket and the sheet metal open so that area would stay dryer. FWIW.
