Summary

Bolts to Openbeam 15x15 and has two 90 degree opposed passages for small cable ties to tidy your wiring. The base is 14mm square, so it will fit with plenty of clearance between other parts. The hole in the top is a tight fit, but when the screw pops through, it acts as a keeper.

The local electronics/hobby store has stick-on ones, but they're 21mm square, and 50c each, so print a handful and go crazy.