Completely understand. Yes, that connector is not connected to anything electrical. But (if memory serves) only connected to the Christmas tree fastener holding it to the rear crossover bracket. It is weird that it is there, but I'm sure JLR uses this same engine harness in another application; and, in that application, it is used
Just guessing here, but I would expect you push in a bit to take tension off of the retainers, then push in the ridged parts (likely one on the back side too, at 180* from the one you see) to release the retainers, then pull off from the barb.