TMML is an XML DTD designed for the documentation of Tcl, Tk, and other Tcl extensions.
See http://www.hwaci.com/sw/tcldoc/beta2.tar.gz for the second public beta release of the XML sources for the core Tcl/Tk documentation. http://www.hwaci.com/sw/tcldoc/html/ is the web site which discusses more about the effort. Also, see
http://www.hwaci.com/sw/tcldoc/html/ for web based versions of
the Tcl and Tk man pages. Some more up to date work on this effort has been put on http://tmml.sourceforge.net/ .