I think it would be beneficial if Map could read all fields within a shapefile.
We have a shapefile that is used to submit to a regulator that has a field named 'SAHPE*' that describes the file's geometry (polygon for my application). It shows in ArcMap but not Map.
I tried adding new within Map using the Schema editor but it disappear.
I believe the regulator does an automated check for specified fields and it will be there but that still doesn't explain why Map won't show it (????).