In commits by Simon McVittie on Oct 5, 2014, the following was added to `cgitemplate()`:

    b0a35c81 (Simon McVittie   2014-10-05  61) 	my $topurl = $config{url};
    3b8da667 (Simon McVittie   2014-10-05  62) 	if (defined $cgi && ! $config{w3mmode} && ! $config{reverse_proxy}) {
    b0a35c81 (Simon McVittie   2014-10-05  63) 		$topurl = $cgi->url;
    b0a35c81 (Simon McVittie   2014-10-05  64) 	}

I am trying to determine what was intended by this change.  The variable `$topurl` is not used again in this function, so this is essentially dead code.