/usr/lib/python3/dist-packages/matplotlib/sphinxext/ is in python3-matplotlib 2.1.1-2ubuntu3.
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/usr/lib/python3/dist-packages/matplotlib/sphinxext/__init__.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/mathmpl.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/only_directives.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/plot_directive.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/__init__.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/conftest.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/test_tinypages.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/tinypages/
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/tinypages/_static/
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/tinypages/_static/README.txt
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/tinypages/conf.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/tinypages/index.rst
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/tinypages/range4.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/tinypages/range6.py
/usr/lib/python3/dist-packages/matplotlib/sphinxext/tests/tinypages/some_plots.rst