Talking to Kevin just now, we both noticed the following:
"Rule 3.8.1: Brake Lights: At all times, each car must have at least
one working brake light that is easily seen from the rear. The light should be located where a mild rear-end impact won't break or obscure it. Good spots include inside the rear-windshield area; on top of the parcel shelf; and on the deck at the base of the rear-windshield area."

So we only need the 1 brake light on the spoiler as this team has done. This is how there were able to ditch the entire rear light assemblies. Great idea. They do have some other light or perhaps just a reflector in the middle/top of the license plate holder... They could have removed more plastic from the back of the car there.