Torben Weis <weis@kde.org> wrote a perl script that proved how simple it was to parse the KDE Library headers to generate documentation that looked like the Qt documentation.
Sirtaj Singh Kang <taj@kde.org> took it upon himself to extend this program to turn it into a full-fledged application. He found out the hard way that while it takes 10% effort to parse 75% of source, the next 10% takes another 100%.
KDOC 1.0 still used some of Torben's source, but never really worked properly but was useful enough for a year or so.
KDOC 2.0 is a complete rewrite of KDOC, and is much more extensible and robust, even though it has scores of new features that were impossible to put into 1.0.