HTML documentation is not built reproducibly (Sphinx)

The present sphinx configuration leads to sources being included in the html build inside the _sources directory (because html_copy_source is set to true by default). Inside this directory the file _sources/examples/index.rst.txt contains the build path, e. g. for one of my builds:

[...]
    :download:`Download all examples in Python source code: examples_python.zip <//build/python-lark-utTVdH/python-lark-0.10.0/docs/examples/examples_python.zip>`
[...]
    :download:`Download all examples in Jupyter notebooks: examples_jupyter.zip <//build/python-lark-utTVdH/python-lark-0.10.0/docs/examples/examples_jupyter.zip>`
[...]

This renders the HTML documentation build process unreproducible (see https://reproducible-builds.org).

Is there a particular reason why you include the sources in the html build? If the only reason is that this behaviour is the default, one possible way to fix this would be setting

html_copy_source = False

in docs/conf.py.