I wonder if the two tangs at 9 o'clock are the remnants of the hinge. The lid / door is missing of course. I can imagine the teeth a noon and 6 o'clock are the index for a bail or bar on the underside of the missing lid, that would give the operator an option of different levels of openings, like the different ridges in walls of your oven let you move the rack closer to or further from the heat.

Not an exact comparison...

The pair of teeth closest to the hinge would be the widest partial opening, then click click click click, lower and lower as the support bar moves farther from the hinge.