Hi,
Sorry I only checked (and answered) to your comment on mentors.d.n. I
just saw now you left the same message here.
First, thanks for reviewing my package.
The sphinxdoc debhelper extension[1] helps to install documentation
build with sphinx (python3-sphinx package).
Can you check you installed all build dependencies, especially
python3-sphinx which depends on sphinx-common which itself provides the
dh_sphinxdoc command?
Well, I guess that now Bullseye soft freeze is gone, it's less urgent
matter.
Best regards,
Thomas
[1]: https://manpages.debian.org/buster/sphinx-common/dh_sphinxdoc.1.en.html