1968 Nova front drum brake question

[DougsL78]

Doing a complete rebuild on the front drum brakes on my 68 L78 Nova.

There is one piece I can’t figure out what it’s for, and doesn’t come in any rebuild kit that I can find.

Behind the pin and up against the backing plate- there is an approx 1” square piece of sheet metal with the corners bent up- almost like a locking mechanism… although I don’t think can actually “lock” anything. What the heck is it, and what is it for? And I suppose I will need to make one….