I couldn't compile v7-0001 and I am testing with the older v6-0001 (of
which I still had an instance).
So the problem below may have been fixed already.
If you add a generated column to a file_fdw foreign table, it works OK
wih VIRTUAL (the default) but with STORED it adds an empty column,
silently. I would say it would make more sense to get an error.
Erik Rijkers