spawn-fcgi help confusing

(As spawn-fcgi seems to be closely related to lighttpd I thought that it would 
be best to post to this list.)

The help given by the spawn-fcgi tool is a bit confusing:

" -f <fcgiapp> filename of the config-file"

Am I supposed to specify the FastCGI application or its config file? For me it 
(logically) only works when I specify the application/binary, 
e.g. /usr/bin/php-cgi

Maybe this should be clarified.

Steffen