Re: Faces customization group linked from mode groups

[Richard M. Stallman]

      node name, as in @code{"(emacs)Top"}.  The link appears as
    ! @samp{[Manual]} in the customization buffer.  When this link is
    ! invoked, the built-in Info reader is started on @var{info-node}.

Could you rewrite that in active voice?

    ! Link to a web page; @var{url} is a string which specifies the
    ! @acronym{URL}.  The link appears in the customization buffer as
    ! @var{url}.  When this link is invoked, the WWW browser specified by
    ! `browse-url-browser-function' will be called with @var{url}.

That too.

    + @item (emacs-library-link @var{library})
    + Link to an Emacs Lisp library file; @var{library} is a string which
    + specifies the library name.
    + 
    + @item (file-link @var{file})
    + Link to a file; @var{file} is a string which specifies the file name.

I am not sure what it means to "link to a file".
I think you need to explain what that means.

    + @item (function-link @var{function})
    + Link to the documentation of a function; @var{function} is a string
    + which specifies the function name.
    + 
    + @item (variable-link @var{variable})
    + Link to the documentation of a variable; @var{variable} is a string
    + which specifies the variable name.

Likewise here--what does it mean to "link to" these things?

    + 
    + @item (custom-group-link @var{group})
    + Link to another customization group.  Invoking it creates a new
    + customization buffer for @var{group}.

That's example of saying clearly what the link means.