Recently a change was made in the python client libraries template for noxfile.py to use newer version of sphinx in the nox session that generates the docs. There is code in owlbot.py to use sphinx<3.0.0 which reverts the sphinx upgrade. When I ran nox -s docs with a newer version of sphinx, there were several sphinx warnings. I'll dig into the warnings and propose fixes. The workaround to downgrade sphinx in noxfile.py should be removed in the PR that fixes the warnings.