Walking through a home you might notice a non descriptive box in every room, some may have numbers on a dial 50, 60, 70.
What you are looking at is a thermostat for the radiant heat ceiling.
The house is not heated by air coming out of a vent but wires embedded in the ceiling. The wires heat up much like a toaster or hair dryer element and warms the ceiling which radiates the heat down into the room.
The colored photo taken with an infrared shows the lines of the heating wires (in red) warming up, the blue is the gap between each embedded heating panel. These infrared ceilings were very popular in the “all electric” homes of the 60’s and 70’s and require very little if any maintenance.
They are easily damaged by screws or nails used to attach something to the ceiling.
Do not attach anything to the ceiling without checking using an infrared camera that the area is heating element free.
They are usually repairable if non functional.