This is a camera mount for attaching a USB camera (any 38x38mm camera with a 28x28 hole pattern). Originally this was designed to be used with this Arducam IMX291 board which comes with a 100 degree diagonal FOV (90 horizontal, 68 vertical).
This mounts the camera from the outside of the enclosure since there isn't much space inside the enclosure to capture a full view of the built plate and this helps to avoid overheating of the camera.
Why is the mount so big? To avoid reflections off the plastic window getting into the camera, the mount roughly covers the entire window space the camera looks through.
How to control the USB camera? You can't directly connect the USB camera to the Prusa board. You will need an external computer (e.g. a Raspberry Pi with OctoPrint) to control the camera.
Installation:
There is an optional fan-lid.stl that can be printed to mount an extra 30mm 5V fan on top of the camera to prevent overheating. To use it:
The author marked this model as their own original creation.