Ticket #28449: 28449-the_content-orphans.patch

src/wp-includes/post-template.php

@@ -220 +220 @@
          */
         $content = apply_filters( 'the_content', $content );
         $content = str_replace( ']]>', ']]>', $content );
+    /** Add   before last word to prevent widow */
+    $content = preg_replace('/\s([\w]+[.,!\:;\\"-?]{0,1})$/', ' \\1', $content);
         echo $content;
 }