It's an hygrometer/thermometer holder that appear flush with the frame and so doesn't conflict with Z axis whatsoever
EDIT: It does conflict with the cable behind the nextruder, so not suitable if the nextruder get at a high Z axis after a print, because it would never been able to home properly.
However the print is unfriendly for 3D printers, I dont know how to make it nice without supports. So I did a straight cut and a gluing but if you guys have a better idea let me know.
Tested on my MK4 only. Give me feedback if it's MK3 compatible, I don't know much about Prusa yet
The author marked this model as their own original creation.