I got at the fleamarket a (Polaroid-made?) camera-body with fixed packfilm back similar to the type 405 cassette.
It has a flipping accessory shutter, several tripod threads and a standard flashlight/accessory shoe.

The front has a coupling, seemingly for a lens/shutter assembly.

As I realized that the packfilm back was just screwd onto the body I bought it just to have that back to custom build some instant camera.
Seeing that accessory shutter I also considered as alternative use to keep it as it is and just install a pinhole.

Seemingly someone else had the same idea, as seen in this photo (the only one of this thing I found after 1/2h of searching):


Out of sheer curiosity:
What was the original use of it?