This ball and cup design can be used for many an application.
This specific set was made as a replacement of the arm in the Modular Minimal Pi Case (https://www.prusaprinters.org/prints/32789-modular-minimal-pi-case-with-picam-case-mmpic-picc) ... the arm on that was a bit ... flimsy.
This design seems to hold up better and is more easily adjustable and more modular.
You can mount this system on anything that has a 10mm hole with a thread (right turning).

Print instructions

The ball-side with thread (Basic BC screwon Ball) is designed to be printed standing and has his own support designed with the file (will be easily removed once printed).
None of the files need extra support. The longer peaces might suffer from a slight "wobble" but i'm not sure anyone will ever need the long parts ...