Sphinx is a tool that translates a set of reStructuredText
source files into various output formats, including HTML, ePub,
LaTeX and plain text. Sphinx was originally created for the Python
documentation, but it has excellent facilities for the documentation
of software projects in a range of languages.

All Sphinx dependencies must be built with Python 3 support and since
there are many different way of providing this, the following packages
require special build instructions not captured in REQUIRES:
- python/python-urllib3: install python/python3 first
- python/idna: install python/python3 first
- python/python-chardet: install python/python3 first
- python/imagesize: install python/python3 first
- python/alabaster: install python/python3 first
- python/pytz: install python/python3 first