Not answering the OP but a lower post:
The third brake light in the middle of the rear window is very useful when you’re in a traffic queue.
You get to the front of the queue and the guy behind is waiting for you to pull out so he can go as well, he can see your centre light a lot better than your side lights.
I always keep my foot on the brake in these circumstances so he knows if I’m going or not. Must save a lot of rear-end collisions.