What is this

Im not seeing anything on those diagrams and Ive checked out other ones, nothing! Im kinda surprised that this may be a optional item on cars since not everyone has one. I just assumed it was stock on all vehicles.

Interesting that Logan also has it and its not hooked up. Obviously this part is not needed for the function of the car.

Logan, do you have A/C in your car and does it work? I believe it has something to do with that since, just trying to figure out if it has to do with that.