As far as I know there is none, there have been several attempts at writing configuration guides/howto’s, but most of them have stranded, which in fact is logical as you could never cover all of fvwm’s configuration options in that way…
Fvwm Beginners guide
zensites.net/fvwm/guide/index.html
Nice work!
But what still is required is a well structured reference for Fvwm including complete descriptions of the programming interface.
Is there anyone interested in starting a project for that?
Roland
That would be pretty handy indeed, the wiki doesn’t say much on that topic…and the Fvwm man pages don’t do so either…
Unfortunatly I don’t have the time to spare to start off something like that, but I’m sure other people will, you might want to contact some people from the fvwm wiki, maybe they are interested 
Cheers
tBD