Error displaying widget: model not found

Start by reproducing the notebook snippet and inspecting the JupyterLab extension list. Compare ipympl 0.8.8 with the jupyter-matplotlib v0.10.1 extension, especially the report that an older extension is overshadowing it; done means the widget displays without the model or unregistered-module errors.

Describe the issue

%matplotlib widget
import matplotlib.pyplot as plt

plt.plot([0,1],[0,1])

results in

Error displaying widget: model not found

The javascript console shows:

Could not instantiate widget
Error: Could not create a model.
Uncaught (in promise) Error: Module jupyter-matplotlib, semver range ^0.10.5 is not registered as a widget module

Versions

 3.9.12 (main, Mar 26 2022, 15:44:31) 
[Clang 13.1.6 (clang-1316.0.21.2)]
ipympl version: 0.8.8
Selected Jupyter core packages...
IPython          : 8.2.0
ipykernel        : 6.12.1
ipywidgets       : 7.7.0
jupyter_client   : 7.2.1
jupyter_core     : 4.9.2
jupyter_server   : 1.16.0
jupyterlab       : 3.3.2
nbclient         : 0.5.13
nbconvert        : 6.4.5
nbformat         : 5.3.0
notebook         : 6.4.10
qtconsole        : not installed
traitlets        : 5.1.1
Known nbextensions:
  config dir: /Users/remco/.jupyter/nbconfig
    notebook section
      toggle_all_line_numbers/main  enabled 
      - Validating: OK
      equation-numbering/main  enabled 
      - Validating: OK
      toc2/main  enabled 
      - Validating: OK
      collapsible_headings/main disabled
      nbextensions_configurator/config_menu/main  enabled 
      - Validating: problems found:
        - require?  X nbextensions_configurator/config_menu/main
      scroll_down/main  enabled 
      - Validating: OK
      jupyter-js-widgets/extension  enabled 
      - Validating: OK
      contrib_nbextensions_help_item/main  enabled 
      - Validating: OK
    tree section
      nbextensions_configurator/tree_tab/main  enabled 
      - Validating: problems found:
        - require?  X nbextensions_configurator/tree_tab/main
  config dir: /usr/local/etc/jupyter/nbconfig
    notebook section
      jupyter-matplotlib/extension  enabled 
      - Validating: OK
      jupyter-js-widgets/extension  enabled 
      - Validating: OK
JupyterLab v3.3.2
/usr/local/share/jupyter/labextensions
        jupyter-matplotlib v0.10.1 enabled OK
        @jupyter-widgets/jupyterlab-manager v3.0.1 enabled OK (python, jupyterlab_widgets)

Other labextensions (built into JupyterLab)
   app dir: /opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/share/jupyter/lab


The following source extensions are overshadowed by older prebuilt extensions:
    jupyter-matplotlib