Just packed up to return from our Christmas holiday & thought, I wonder what this bracket is for?
The bracket sits just below the slide topper awning rail & looks like it would accept some kind of stay, there is only one bracket, nothing the other end & I don't recall seeing anything that would locate into it, any ideas?

 

It is to stop the awning from unfurling while traveling, should the wind catch it and the spring tension not be enough to hold it. Try unwinding your topper with the slide in and the arm should hit it before the roller unwinds very far. It very rarely comes into play.

Steve

 

Ah, that makes sense. You're not an RV tech for nothing!
Thanks & happy new year