A question about Extension documentation

I mentioned last month that I am developing an experimental lightweight fork of APC intended primarily at shared hosting / CGI / FastGCI stacks. I have a simple Q. I am used to developing with the full documentation set embedded in any source that I develop. (Doxygen is my documentation tool of preference, BTW). I realise that this isn't the common practice with PHP and the PECL extensions, however, there is some discussion of "Docgen" and some dead links on the PHP wiki. There are a few "Docgen" products on the Internet, but on a first scan, these aren't what PHP seems to be referring to. Not putting proper documentation into my code is quite frankly doing my head in, but I don't want to frustrate any documentation systems that you do have in place, so I would like to include a sensible level of extension documentation within your documentation framework if at all possible. Can someone please point me to the documentation and installation for your Documentation system so that I can use it -- and the github links to documentation source for example extension. Sorry I might be being dumb, but I just can't find it. Regards Terry Ellison