I can't tell you what exactly it is, but it gets plugged into another round connecter near the bottom of the fuse box. I just did my wire tuck and that was one of the plugs i moved.
The car has been sitting for 8 months. I've been busy getting other things in order for it before I start cleaning. No need to clean them until I'm done working in the engine bay. It'll be clean when the time comes.