Where are plugin functionality descriptions?

[Larry Evans <cppljevans suddenlink net>]

The web page:

  http://projects.gnome.org/gnumeric/doc/sect-configuration-plugins.shtml

contains:

 If the box contains a check mark, the plugin has been activated and its
 functionality should be available.

However, where is that "functionality" described?  I've tried
selecting the function button and then looking at the categories,
but it's not obvious which to category a given plugin belongs; hence,
I don't know where to look for a description of the functionality.

-Larry