Heat shielding piece fell off

I had some heat shield rattling and wheel noise, took it to tire place to check out the wheel, and they came back with a piece of heat shielding that they said "just fell off." The problem is, I can't seem to figure out where exactly it came from so that I can bolt it back on. I've looked at parts diagrams and can't find a heat shielding piece that looks anything like this. It's pretty small. I'm not really a car guy, help me out please!