I bought a box of stuff that included a bulk loader, and that included… mystery film. Stand developed in caffenol, I figured out it’s Plus-X which tells me it’s pre-2003 (?), but I’m curious if the edge markings give clues more specific than that.
Here’s a frame with the full edges of the film included:
This is really just curiosity - my experiments so far seem to indicate it’s happiest at about EI 50.
Here’s a frame with the full edges of the film included: