It's going to be a specialty bracket for something. Unless you have that 'something'....it's basically worthless.
A good example is a TV mount I installed for my MIL. It came with extensions to adapt to larger TV's. I didn't need it....so now I have 4 strips of metal with holes in it. I saved them (it's what is garage guys do).
So a few years from now when I'm dead and my boys are cleaning out the garage, they will post it on GJ and ask "What is this thing?"