loose wires in engine bay

So, I'm not a computer guy so much and I've been mia from this board for the longest. Not sure if this is the correct place to put my question, I'm sure more advanced folks will correct my path if needed.

I went to do my weekly oil check this am and noticed this bare, zirc looking fitting, then I noticed the hanging, loose, wire.

Now, I am a Vet with memory issues, but I swear I remember seeing the fitting g in the past and thinking "damn, that's an odd place for a zirc fitting" then looking at it and realizing it's just a nub....but I can't recall ever seeing the hanging wire.

I'm just trying to figure out what's what. I've had no issues with the car. I know it's probably super simple, but as I look at it, my brain just can't make sense of what I'm seeing.

Thx in advance.

P.s. I don't remember how to post my pics here. Sorry guys, thanks for your patience.