This works with the Rotor Riot CL1 frame, and would likely work with others. You will need a M5 nut, or find one from a broken GoPro mount. It works in the front or back, 32 or 33mm spacing. I used 8mm M3 screws to replace the 5mm ones holding the top plate on to mount this to the drone frame.
Printing: I printed two, one in PLA, and one in TPU, and I would recommend TPU to help reduce vibration in the video. No supports or rafts are necessary. I would recommend 3+ perimeters, top and bottom layers for durability. Infill should not make too much of a difference, but I used 30%.
I attached the Fusion 360 .f3d file if you would like to modify.
The author hasn't provided the model origin yet.