It may not be a handle, it may be a track hanger where the handle portion is up inside a track with an opening on the bottom and the loop is on the underside. I have also seen this style also for curtains.
Not sure anyone can tell you what it was used for. It's got a brass handle, probably off of a gas or water valve, or car, and then some home made iron gizmo attached. Somebody needed it for something, and patched it together. You could try posting it three times.
I'm not caffeinated enough to slosh that far into the memory bank. But I think I've seen something similar on a tractor. Give a try on some of the farm equipment sites, look for side cover latches. Hope that helps! Off for a cup!!!!!!!!!!