An anyone identify?

Pegs are 9 5/8 on center

Wixtedjj - the hinged bar looks like a registration device for a 10 x 15 Heidelberg platen. An acetate sheet is attached to the bar and the pegs fit into the Heidelberg chase. The 9 5/8 centres match. I made my own but it would be nice to have a genuine part.
Heidelberg part number T2450F

Frank is the winner! A fairly elusive accessory for the Windmill.

Thank you mikefrommontana for the confirmation, I use my home made version all the time for multi colour printing with polymer mounted for honeycombe base, makes registration so much easier.

They are correct. I use it all the time to locate plates to proper location and also when matching foil die placement to digital printed sheets as well. After some practice you will get it close enough to speed up your setup

I’ve used the equivalent device from the KS cylinder, with the necessary attached mylar to take an impression from the form. I also attached stripping pins to this device, located matching pins to my Vandercook head bar, and my platen chases, so I could register a secondary mylar across different press platforms with minimal fuss.