Identify this connection

I was topping up my oil this morning and noticed a problem with a wiring connection. In the attached picture, there are two of these connections side by side top-front of the valve cover. The empty bolt hole to the left of the one pictured is where the broken one goes. It is currently off-camera being glued. Does anyone know offhand what these are for? I suspect they are some sort of central grounding point, perhaps associated with the fuel injectors. They come out of the fuel injector harness. Wanted to make sure these aren't some sort of sensor, knock detection or the like. They are odd, three solid brown wires all of differing gauge. The large wire goes right to the lug and the other two medium and small gauge wires are encased in a white formed flexible plastic sleeve. Those two may or may not make connection with the lug. I would have to do too much destructive inspection to know for sure. The lug that is being repaired was flexed backward, which cracked the forward-facing surface of the white plastic portion. I was able to look into the crack and see some stranded copper wire. I know I wasn't the big oaf that broke it, probably the dealer tech that was fixing my headlight harness a couple weeks ago. I will spend some time looking through the wiring diagrams I have (Thanks again for those, Mendel).

 

Thanks, that's what I thought it was. It just looks a little peculiar. Wouldn't be the first time a bit of sensitive electronics was hidden in a non-descript connector.