Well poking around, I now see many missing modules. Fixing them is probably beyond my ability and motivation.
Below are just the top-level ones
The worst being a missing module for PyInstaller itself which apparently does the imports which might explain why so many are missing. I had installed PyInstaller via pip.
missing module named pyimod03_importers - imported by /usr/local/lib/python3.8/dist-packages/PyInstaller/hooks/rthooks/pyi_rth_pkgres.py (top-level)
missing module named 'pkg_resources.extern.pyparsing' - imported by pkg_resources._vendor.packaging.markers (top-level), pkg_resources._vendor.packaging.requirements (top-level)
missing module named _winapi - imported by encodings (delayed, conditional, optional), subprocess (optional), test.support (delayed, conditional), multiprocessing.connection (optional), multiprocessing.spawn (delayed, conditional), multiprocessing.reduction (conditional), multiprocessing.shared_memory (conditional), multiprocessing.heap (conditional), multiprocessing.popen_spawn_win32 (top-level), asyncio.windows_events (top-level), asyncio.windows_utils (top-level)
missing module named _overlapped - imported by asyncio.windows_events (top-level)
missing module named multiprocessing.set_start_method - imported by multiprocessing (top-level), multiprocessing.spawn (top-level)
missing module named multiprocessing.get_start_method - imported by multiprocessing (top-level), multiprocessing.spawn (top-level)
missing module named _frozen_importlib_external - imported by importlib._bootstrap (delayed), importlib (optional), importlib.abc (optional), zipimport (top-level)
excluded module named _frozen_importlib - imported by importlib (optional), importlib.abc (optional), zipimport (top-level)
missing module named multiprocessing.get_context - imported by multiprocessing (top-level), multiprocessing.pool (top-level), multiprocessing.managers (top-level), multiprocessing.sharedctypes (top-level)
missing module named multiprocessing.TimeoutError - imported by multiprocessing (top-level), multiprocessing.pool (top-level)
missing module named multiprocessing.BufferTooShort - imported by multiprocessing (top-level), multiprocessing.connection (top-level)
missing module named multiprocessing.AuthenticationError - imported by multiprocessing (top-level), multiprocessing.connection (top-level)
missing module named pkg_resources.extern.packaging - imported by pkg_resources.extern (top-level), pkg_resources (top-level)
missing module named pkg_resources.extern.appdirs - imported by pkg_resources.extern (top-level), pkg_resources (top-level)
missing module named msvcrt - imported by subprocess (optional), getpass (optional), test.support (delayed, conditional, optional), multiprocessing.spawn (delayed, conditional), multiprocessing.popen_spawn_win32 (top-level), asyncio.windows_events (top-level), asyncio.windows_utils (top-level), /mnt/AllData/hacking/eval/rdiff-backup/src/rdiff-backup (optional)
missing module named rdiff_backup._librsync - imported by rdiff_backup (top-level), rdiff_backup.librsync (top-level)
missing module named rdiff_backup.C - imported by rdiff_backup (top-level), rdiff_backup.rpath (top-level), rdiff_backup.robust (top-level), rdiff_backup.eas_acls (top-level), rdiff_backup.win_acls (top-level), rdiff_backup.regress (top-level), rdiff_backup.Main (top-level)
missing module named macresource - imported by MacOS (top-level)
missing module named _yaml - imported by yaml.cyaml (top-level)