Weickert

I am new to this forum and was hoping someone could help me out with a wiring harness question? I have a 2019 F150 XLT and just recently had a second remanufactured long block installed in the vehicle (long story on the engine issue, but original engine was replaced after 47K miles and the replacement remanufactured long block only made it 3K before it had to be replaced - severe oil consumption) and upon receiving my truck back from the dealership, I found several issues with workmanship and not reconnecting parts. When inspecting the wiring harnesses for proper connections and security, I found one connector end that was not attached to anything....and I do not know what the connection is for. The wiring harness is located in the engine compartment on the drivers side, just below the brake fluid reservoir. The part number on the complete wiring harness is KL3T-12A581-CEF. There was only one smaller connector that was not connected to anything, and I want to understand what the connector is for and if it is supposed to be connected somewhere. See photos of the connector in question below. Any help would be greatly appreciated.

Bluegrass

As near as I can tell, the Part number is for a large Harness with many different parts under one number.
Its cost ranges from $200 to $500 if that Part # is purchased.
It may be part of the Brake fluid Reservoir level Sensing. Something in the immediate area, the plug will reach.
More might be learned if the system were Diagnosed for all codes possible and come up with a B, C, or U code that would lead you to the part of the system failing Diagnostics.
P codes are for the Engine/Trans..
Good luck.