I've seen in some of the newer homes they frame the wall space above the mantle with crown moulding. Most are square but some are arched. It can be small as a box above the mantle or as large as covering the entire wall above the mantle. Does anyone what this is called?

I would like to find some pictures to get some ideas, I can't do a search because I don't know what this would be called.

Does anyone know?

Thanks.