Enderman
(Enderman)
7
The whole PCB is 31.6mm diameter.
The small holes are 28mm spacing but I noticed that the side of the hole towards the outside of the PCB is kinda squished flat somehow, so it only is 2.35mm wide in that direction.
Probably something to do with the manufacturing process.
You can just fix them and make them round again by pushing a 2.5mm drill bit or tapered rod through it.