They are just window solid window frames, or "transom window" most discount lumber store have them. Usually the are the cheapeast windows you can get and the easiest and simplest window to make. Normally they have a pair of hindges on the bottom or sides so the window can be opened or closed. Some have chains, rods or in this case sheet metal so they don't open all the way.
Some are mounted on the outside and swing all the way open like a window shutter would and have wire covering the opening. Some tilt in like the one in the pictures and use anything from chains, rods, or other device to keep them from coming in all the way. I have seen some the hang all the way down when open.
The hindges can be mount on the bottom, top, or side. Or you can have pin hindges mounted in the middle.
You can make transom windows from other types of windows, like a double or single hung window. By taking the inner frames out of the larger frame.
They use a wood toggle at the top of these to keep them closed. the Wood toggle can be used to keep them open or closed. I have some detail picture of how to make the toggle, but they are still in the camera.