Audio extra wiring

I installed a new radio into my tacoma today, and ran across 4 wiring harnesses that were plugged into the stock unti, and not the usual 3 I have seen on many write ups here. The stock unit was a 86210-04170 part#, and could not find anything to tell me what the extra harness was being used for. Any one ever seen this? I only used the 2 I knew I needed, and I am sure the one is for the steering wheel controls, which I will tackle another day. The unit ran fine and no issues could be seen, so is this other harness a satellite one? If you need any other info, or pics, gladly will upload them I am at a loss .

 

Just guessing, the smaller left connector is for factory backup cam? and the larger left connector has wiring for the aux jack, steering wheel controls, and some data wires to the can-bus