There are so many uses for shelf brackets! These are shelf brackets, repurposed to frame a window --- what a clever idea. You could do this to define and separate spaces in the same room, too. (Say an entryway and a dining room.
Kitchen window- Rustic, Repurposed Vintage Iron Brackets - simply hung on window frame's interior by cup hooks. This is a clever way to add interest to a room - via Chateau Chic: First Project of the New Year