Ticket #30556: 30556.1.diff

src/wp-includes/widgets.php

@@ -814 +814 @@
                 'after_title' => "</h2>\n",
         );
 
+        if ( current_theme_supports( 'html5', 'widget' ) ) {
+                $defaults['before_widget'] = '<aside id="%1$s" class="widget %2$s">';
+                $defaults['after_widget'] = "</aside>\n";
+                $defaults['before_title'] = '<h2 class="widget-title">';
+        }
+
         $sidebar = wp_parse_args( $args, $defaults );
 
         $wp_registered_sidebars[$sidebar['id']] = $sidebar;