The cygwin-doc source files are kept in CVS. Please see
https://cygwin.com/cvs.html for more information.

BUILD REQUIREMENTS:

bash
bzip2
coreutils
cygwin
dblatex
docbook-xml45
docbook-xsl
gzip
make
texinfo
perl
xmlto

OTHER NOTES:

You may use docbook2X to convert the DocBook files into info pages.
I have not been able to get a working docbook2X installation on Cygwin,
so currently I convert the files on a machine running GNU/Linux.

A few handmade files (cygwin.texi, intro.3, etc.) are found in the
cygwin-doc-x.y-z-src.tar.bz2 package. It also contains the utilities for
building the cygwin-doc-x.y-z "binary" package--simply run each step in
the cygwin-doc-x.y-z.sh script.