Agfa Ansco 7x11 adapter for 8x10 camera

Has anyone ever seen one of these elusive 8x10 -> 7x11 Agfa adaptors? They are mentioned in the catalogs and a few times here, but I have not yet been able to find any pictures of such a thing. Were they actually produced? I have one Ansco 7x11 film holder in my collection of mostly Eastman 7x11 holders. That leads me to believe Agfa Ansco must have produced the back.

The Afga's 8x10 back is only around 11 1/2 square. Smaller than a Deardorff or a Gandolfi. Curious how they managed to do it. Tapered expansion back I assume.