I have a Shapeoko XXL and had to dismantle part of it to fix a problem with the belt in the X/Z carriage. After reassembling it, I found that this screw was left. I can’t remember where it came from and I haven’t been able to find it in the instructions.
It’s similar in size to the ones on the switch plates, but the switch plates all have theirs.
I also have a set screw left over, which is about 2cm long, that I can’t find the place for.
The only part that I disassembled was the X/Z carriage.
that one probably belongs to one of the stepper motor pulleys, they each have two setscrews, and a missing one is not great so you should definitely go back and figure out which pulley that one escaped from