What is this thing?

This may or may not be associated with music stands or equipment. I can’t remember.

I just emptied and re-did my music/video room, and found this bracket in a small box with no labels or anything. I can’t remember what it’s for. I think it’s either audio or video related, but it doesn’t seem to match any of my mic or equipment stands, though it might be. It’s devoid of any branding or part/serial numbers. No markings of any kind.

It folds like this:

More pics:

There’s a sliding mount screw on the bottom:

Thanks!

(Sorry for poor lighting, MacBook Pro 15” for scale)