what is this (non-important) plug?

hi all, whilst tackling some front-end bodywork issues, and possibly an AC condenser change, I noticed the plug below, bridged with a paperclip.

I don't think it's a parking sensor (I have 2 of those with plugs already) nor is it anything to do with the fog lights.. a couple of clues :
It seems to want to be lower bumper area, passenger side slightly.
The ambient temp sensor reading is always -40C, although I don't know where that sensor should be, there is nothing obvious anywhere at the front of the car
When I pulled the paperclip out, the reading didn't change (maybe that's a red herring)
A temp sensor on ebay seems cylindrical, whereas this plug is more oval.

any thoughts while I am down there doing other stuff?

thanks as always
John