This replaces the stock cover for the X-Axis motor on an Ender 3. This provides a slot, wide enough to accommodate an M3 bolt to connect to your favorite camera. Standoffs on the inside of the box give the X-Axis limit switch a place to sit using the stock screws.
Take care when removing the stock cover, as the X-Axis limit switch, and X-Axis motor are connected to this, and can fall out when all 4 bolts are removed.
I paired this with a mount for my Logitech C920 (https://www.thingiverse.com/thing:3603382).
Rotate this to print standing on the 4 screw holes. Supports touching build plate.