My hallway has a light like this that was removed from what I can only guess was water damage and the accompanying upstairs bathroom renovation.

It's astounding to me that they would go through the trouble of renovating the bathroom, but not have reinstalled the light so that the hallway isn't a dark safety hazard... 😒

I used to work summers as an apprentice electrician. The amount of crazy wiring I saw in old houses was (heh) shocking. Sometimes it was just that it was old. Real old houses sometimes just had bare wire wrapped in silk. ... And a few decades later that silk was frayed and crumbling in the walls and needed replacing.

My current house was wired at a time when copper was more precious, so it was wired up and down through the house, with circuits arranged by proximity, not necessarily logic. When a certain circuit in my house blows the breaker, my TV, PC and one wall of the master bedroom all lose power. The TV and PC are not in the same room either.