I am working with archaeological data (specifically, a site map drawn in CAD) for a site whose real-world location is unknown. The site was excavated using an arbitrary grid with a datum of 0 easting and 0 northing. I know that the unit of measurement on the site was feet. Previously, I was able to work with similar files in ArcMap, where it was possible to work with CAD maps that did not have a defined coordinate system or projection and the map units could also be set to feet; however, this is not possible in Arc Pro for some reason: it seems the map units are read-only and set as meters and not feet.
My question: Is this a bug?
The file I'm working with will have no base map in the real-world. It is simply a site map in order to do intra-site analysis of map features using GIS.
Thanks for input!