If the author sees this: please copy/paste the manual in your README instead of including an image with text on it. You’ll help blind people and search engines.
But, yes, that is the manual page I converted from (actually I grabbed it from the tarballs linked in the README - should be the same thing). My entire experience of troff would fit on the inside of a Rizla packet with some space to spare, but looking at the original I think it was using some special macro package that doesn't exist on modern systems. So I re-wrote it to use `-man` macros as best I could, but also included the original man page source for anyone that thinks they can do a better job in future.