References for TeX and Friends is an ongoing
project which provides a help file for LaTeX (and
its friends like ConTeXt, Metapost, Metafont,
etc.) using a state-of-the-art source format,
DocBook/XML. Various output formats can be
generated from the source file. Anyone can write a
converter for any desired output format. Because
the source file is XML, the easiest way to do this
might be to use XSLT.