We have a 2016 20CB. Our is a bar that also has the backup camera. I believe it is marker and third brake light. Will verify tomorrow and report back to be sure.
I have to work on our 20CB tomorrow. A squirrel put a couple small holes in the high pressure fuel line from the tank to the fuel rail. Third weekend I have tried to R&R the fuel line.
UPDATE/CORRECTION: I just checked our 20CB. The top bar is just marker lights, no third brake light function. Evidently the dual brake lights on each side let them not put the third middle brake light in.
Correct just a marker light not a third brake light. I took it off only to find two wires. This is confirmed in the wiring diagram. Thanks for the reply Jay safe motoring