I forget mine is there, and I never use it. What use can you have for it? It can't hold sunglasses that well, maybe toll tickets or something? My engineering theory.....I would imagine it is probably held on with molded in posts and some of those metal rings that slip over the post, and are a B to get off. Or it is glued on. Either way I think you'll have to pull the headliner to do it right. Why do you ask?
It reminds me of those funky fold down lights in the Fox body cars. Again, out of sight, out of mind.
Call the dealership to get a part number.