Use noopener

Author: philwareham

dist/classic/classic.php

@@ -100,7 +100,7 @@ function footer()
 
         $out[] = href('Textpattern CMS'.sp.span(gTxt('opens_external_link'), array('class' => 'ui-icon ui-icon-extlink')), 'https://textpattern.com', array(
                 'class'  => 'mothership',
-                'rel'    => 'external',
+                'rel'    => 'external noopener',
                 'target' => '_blank',
             )).
             n.'('.txp_version.')'.

src/classic/classic.php

@@ -100,7 +100,7 @@ function footer()
 
         $out[] = href('Textpattern CMS'.sp.span(gTxt('opens_external_link'), array('class' => 'ui-icon ui-icon-extlink')), 'https://textpattern.com', array(
                 'class'  => 'mothership',
-                'rel'    => 'external',
+                'rel'    => 'external noopener',
                 'target' => '_blank',
             )).
             n.'('.txp_version.')'.