Part ID - small plate bolted to chassis

[Russ.W.]

Can anyone tell me what this is used for?





The original was pretty much ruined, but I had my body guy make up a new one when he repaired the chassis.

It's a piece that sits between the lower rail of the chassis, and one of the rear cross braces. I removed it as I needed to repair the frame under that section, but have no idea what it's for. I don't recall removing anything from it during the tear-down.