If you go into the trunk area...and squirm you way around,as it's hard to see it, you will see this brace is there to support each corner of the quarter panel/deck panel, at each corner of the rear glass..to give it support. My guess...to beef it up at each corner of the glass, as well gives support to the quarter panel. Sorry for the picture..I was on my back, taking a picture upside down...and had to wiggle into the perfect spot to even get the picture