[McLaren-TAG]

it's more than likely an old cellular phone antenna... I installed countless of those back in the day. Those unfortunately were the horrible antennas I never liked using. The foil Ts to the side were to create a ground plane. The only thing holding them there would have been dual sided tape and if the intaller felt like really securing it then there would have been four dabs of silicone at the corners.

Heat, a razor blade to get things started and then a spudge tool and patience... lots of patience.

EDIT: taking a better look at your pics... there doesn't seem to be any silicone in the corners... heat it and the dual sided tape will loosen up and you may even be able to twist it off or pry it off slowly with your hands.