I think it's a broken rear seat frame (upper part of the left side of the back)...you can see the separation around the vinyl, and you can see the broken part of the metal). I could conceivably get someone to weld it...but then I'd be without a seat for a few days, and this is a daily driver.
I'm (for now) wondering what either aftermarket (cheap) options might be, or a seat replacement...fortunately, the seats are black, so it's a fairly common color.
AFARR