This is a spare part for the snap-lock mechanism of a Fujica MA1 - a cool retro camera from the 80ies. The broken part has some complex overhangs this is only a replacement for the thin lid that actually broke off. It needs to be glued onto the remaining part.
If the small lid that snaps in to close the camerabreaks of just print this part and glue it into the cavity of the remaining part. You need to cut the triangle shaped thing that actually snaps in into the right triangle shape with a knive. I modeled it like this because the RepStrap I am using does not have enough resolution to print the triangle in a smooth enough way.