Front license plate mounting

My 2013's front license plate is mounted directly to the bumper cover in a slight depression with no bracket. It seems these cars were supposed to have a special bracket, but somehow I don't have one.

For tight city parking, I'd like to have some kind of extra thick rubber bumper protector for the license plate bracket, but first I'd like to know what's underneath the bumper cover at the license plate attachment points. I haven't had any luck finding a photo or diagram online that adequately shows what's under the plastic skin. Is it a plastic insert then styrofoam energy absorber, or is there any kind of structure?

I would probably get this "Luv Tap Bumper Thumper," but I don't think it'll fit in that small depression.

I could also get some generic rubber bumpers and mount them with the license plate mounting screws. Nothing is going to look great, but I'm trying to keep it from becoming one of those city cars with a hundred license plate impressions in the bumpers.

Any ideas?

 

Thanks, Brandon. I'd seen that diagram before, but I couldn't quite follow the exact attachment points. I think with that picture and the text (sadly, no more images) from this thread below, I understand the structure and attachment of the bumper skin and license plate.
HOW-TO: Front bumper removal | PriusChat

There's apparently nothing substantial behind the license plate, so any extra bumper that concentrates the force too much will just deform the bumper skin and styrofoam behind it.

It looks like that Bumper Thumper tapers toward the rear and might actually fit in the little depression, so I'll give it a try. I might put a metal plate behind it to spread out the force from people backing into me when they park. Hopefully that Bumper Thumper is slightly more compliant than the bumper skin & styrofoam pad.