It isn't the official document, but at least it's accessible. Netgear (among other manufacturers) licenses ZyXEL's embedded OS for their router hardware. It includes a command-line interface which is otherwise undocumented. I tried spelunking around ZyXEL's website looking for it and got bupkis, squared. Luckily for me, a quick Google search turned up a useful annotated cheat sheet. Even with these clues, by the way, ZyXEL's website is less than spectactularly useful.