python3-mpd FTBFS with python3-sphinxcontrib.devhelp (>= 2.0.0-3) as can
be seen on the reproducible-builds infrastructure:

This is assuming the upstream behaviour of sphinxcontrib.devhelp without
https://github.com/sphinx-doc/sphinxcontrib-devhelp/pull/38, which
generates the obsolete devhelp file format v1 in python-mpd2.devhelp.gz
(#1146167). debian/rules will need some trivial changes to account for
the new version generating file format v2 in python-mpd2.devhelp2, which
makes it compatible with newer help viewers but is not handled correctly
for the current debian/rules. I'll fix this when I can, but for now, I'm
reporting the bug so others don't spend time on reporting or diagnosing
it.

    smcv