What's this?

Thanks, y'all!

X2 Temp sensor.

There are two of them. Yes, there is a gap. One is in the bedroom, the other in the kitchen area. Temperature sensor makes sense.

I can't see it, on my computer or my smartphone.

I believe it's a temperature sensor.

Need to see a wider view of where that is located.

If there is a gap between the top and body, it could be a temperature sensor.

Could be a tie down for a window shade cord.

Looks like a stop for something like a bunk bed.