This is a connector that is bolted to the block. There are no wires attached to it. It looks like a wire connector should be attached to it. I was thinking it might be a ground connector.I think my car had those wires clipped to something back in the day before I rearranged everything. One grouping of wires are for the Knock sensor and the other wrapped wire is for the o2.. I remember when I was replacing the oil cooler lines the o2 sensor had to be disconnected from the chassis harness and A clip like that was taped onto some wires.
What you are seeing might just be the part the harness that used to clip into the end of an o2 sensor connector (See the Barbed end of the sensor connection in the far corner? Mine didn't have that, A clip like what you are seeing just slid onto the back so it does not move around.) Mine broke. I left is as is and just zip tied the wires away from any heat source.