I found this: <!-- m --><a class="postlink" href="http://www.korax-heritage.com/kmod/kmod_manual.html">http://www.korax-heritage.com/kmod/kmod_manual.html</a><!-- m -->
It is online documentation. The devs should make it easier to find. A big yellow link labeled "Documentation". To find it now, you have to click on Project Index, Korax Mod, Overview, and then a subtle "click here" for the manual.
I forgot to mention earlier that I'm using Linux. Figured it wouldn't be a problem, because your sourceforge summary page says that you support Linux (as well as Windows, DOS, and all POSIX OSes). That seems to not actually be the case. I tried the exe under wine, and get an error.
It would be nice if the documentation was more upfront about what was required to play. A "Requirements before you install" section would be nice. You could include that it requires the original Hexen wad. And that it requires Windows. But none of this would be very useful as long as the documentation remains hard to find.
Documentation is important. Hard to do, and not particularly fun, but important.