This is the retainer nut for a center high brake lamp on the roof of a ford van (2008 e350)
Here is a link showing this nut and the assembly in which it goes. In the assembly diagram its labeled "HN1"
This retainer nut is in the roof body and accepts the screw for the center high brake lamp assembly (which you remove to change the lamp inside)
In fact, seeing it you might think it's a permanent part of the roof body, but apparently it's a part that can be replaced.
I'd like to replace one because it's come loose so trying to turn the screw, the nut rotates instead
I can reach a finger into the opening behind the brake light assembly, which I did manage to remove, and feel the tube beneath but I can't budge it, it won't come up
Are they crimped on ?