This is a picture of the rear bumper of a 2016 Chevy Colorado:
On the left is a harness for 4- and 7-pin trailer connectors. In the center is the license plate (blurred).
What is the circular connector on the right? If I pop open the cover I see the inside of a hollow tube with no wires that leads toward the front of the vehicle.
I searched through the truck's manual, paying close attention to the section on trailers and towing, but found no reference to this port.
What is the purpose of the round port on the right?