These are fitted end caps for Apple's 10th gen (and A16, though I've not tested that) iPad. They screw into the RAM mount's Tab-Tite Backplate. I printed mine in ASA since they'll be installed in pickups, 5 wall loops, 45% gyroid infill. The 3MF files should have the orientation, correct, they're modeled to be printed with the ends down, and the screw/connector portion up.
The author remixed this model.
The connection point is based on this wonderful and accurate model. I much appreciate them including the CAD file.