<frozen importlib._bootstrap>:671: ImportWarning: DynamicImporter.exec_module() not found; falling back to load_module()
<frozen importlib._bootstrap>:671: ImportWarning: DynamicImporter.exec_module() not found; falling back to load_module()
An error occured with the extensions manager!
Trying to self-update the package... Failed to update!

Please delete the package manually! (see location below)

Please report this error
------------------------

Report URL: https://gitlab.com/inkscape/extras/extension-manager/-/issues
Location: H:\Inkscape 1.3\inkscape\share\inkscape\extensions\inkman\inkman\inkman
inkscape-extension-manager: 1.0

Not done
Traceback (most recent call last):
  File "H:\Inkscape 1.3\inkscape\lib\python3.10\site-packages\cachecontrol\caches\file_cache.py", line 74, in __init__
    from filelock import FileLock
ModuleNotFoundError: No module named 'filelock'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "H:\Inkscape 1.3\inkscape\share\inkscape\extensions\inkman\inkman\manage_extensions.py", line 61, in recovery_run
    run(args)
  File "H:\Inkscape 1.3\inkscape\share\inkscape\extensions\inkman\inkman\manage_extensions.py", line 36, in run
    from inkman.targets import TARGETS
  File "H:\Inkscape 1.3\inkscape\share\inkscape\extensions\inkman\inkman\inkman\targets.py", line 9, in <module>
    ExtensionsTarget("extension", "Extensions", "extensions", True, filters=("*.inx",)),
  File "H:\Inkscape 1.3\inkscape\share\inkscape\extensions\inkman\inkman\inkman\target.py", line 49, in __init__
    self.archive = RemoteArchive(category)
  File "H:\Inkscape 1.3\inkscape\share\inkscape\extensions\inkman\inkman\inkman\remote.py", line 111, in __init__
    cache=FileCache(CACHE_DIR),
  File "H:\Inkscape 1.3\inkscape\lib\python3.10\site-packages\cachecontrol\caches\file_cache.py", line 84, in __init__
    raise ImportError(notice)
ImportError:
NOTE: In order to use the FileCache you must have
filelock installed. You can install it via pip:
  pip install filelock

When I select Manage Extensions.... any ideas?

I'd report it here: https://gitlab.com/inkscape/inbox/-/issues