Its where a cargo net attaches. There are little flastic T-hook things that screw down to those, and then there are 2 more attached near the rear on the side panels. Not all hatches have it. It was optional and I have only ever seen it on factory sunroof cars. Not sure why, because the sunroof cars have a strap in the hatch floor to hold the sunroof so it may just be a coincadence. Of all the hatch cars I have owned, my 92 LX sunroof car is the only one that has that, and the the net was still in the car when I bought it. I think that with most of the cars that had the net, you would probably find that the net is long gone.