This Cage Plate Is For Which Derailleur?
 

I came across this the other day and have no idea what derailleur it should attach to.

It does have “Catena 3/32” stamped on the inside face.

Please see attach photos.

TIA!
https://cimg2.ibsrv.net/gimg/bikefor...b35c1f7a2.jpeg
Nice, bright and shiny and very solid at 37 grams.
https://cimg6.ibsrv.net/gimg/bikefor...b47640532.jpeg
Upper right shows the stamp.

'60s Record I believe.

This pic is sort of a Record, I mean it's mostly a Record, with the top knuckle of the parallelogram replaced with the one off a "Sport" (not Gran Sport) to get a sprung top pivot, like a Simplex:

https://cimg7.ibsrv.net/gimg/bikefor...189790cb0f.jpg

I have a dirty Record close by. Just cleaned and inspected. The cage on mime, which is 100% original, is identical to the OP's. Mine was harvested from this old Holdsworth...
https://cimg9.ibsrv.net/gimg/bikefor...90c0629d40.jpg
https://cimg0.ibsrv.net/gimg/bikefor...a75b670388.jpg