sqlite3
.load /usr/local/lib/mod_spatialite.so
select spatialite_version();

sqlite-utils :memory: "select spatialite_version()" --load-extension=spatialite

Traceback (most recent call last):
  File "/home/aborruso/.local/bin/sqlite-utils", line 8, in <module>
    sys.exit(cli())
  File "/home/aborruso/.local/lib/python3.8/site-packages/click/core.py", line 829, in __call__
    return self.main(*args, **kwargs)
  File "/home/aborruso/.local/lib/python3.8/site-packages/click/core.py", line 782, in main
    rv = self.invoke(ctx)
  File "/home/aborruso/.local/lib/python3.8/site-packages/click/core.py", line 1259, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/aborruso/.local/lib/python3.8/site-packages/click/core.py", line 1066, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/aborruso/.local/lib/python3.8/site-packages/click/core.py", line 610, in invoke
    return callback(*args, **kwargs)
  File "/home/aborruso/.local/lib/python3.8/site-packages/sqlite_utils/cli.py", line 936, in query
    _load_extensions(db, load_extension)
  File "/home/aborruso/.local/lib/python3.8/site-packages/sqlite_utils/cli.py", line 1326, in _load_extensions
    db.conn.load_extension(ext)
TypeError: argument 1 must be str, not None