Found in a home. First floor, located in a room off a kitchen. About 6 feet off the ground and the crescent shape is open into the wall. What is it?

A questioner said:

Found in a home. First floor, located in a room off a kitchen. About 6 feet off the ground and the crescent shape is open into the wall.

More from the owner: We were looking around the house to find all the outlets and found this in a room connected to the kitchen. We think it’s for wiring behind the wall but seems weird based on the location

Some of the people opinions on it:

Continued on next page