What is Sphinx?

Sphinx is the mainly tool in the Python community to build documentation. See http://sphinx.pocoo.org.

It is now used for instance by Python. See http://docs.python.org and many others

Sphinx uses reStructuredText, and can be used to write your buildout-based application. This recipe sets everything up for you, so you can provide a nice-looking documentation within your buildout, in static html, PDF or even epub.

The fact that your documentation is managed like your code makes it easy to maintain and change it.