Issue #2121209 by swentel, Bojhan: Remove empty 'Web services' category in 'Configuration'.

core/modules/system/lib/Drupal/system/Controller/SystemController.php

@@ -101,7 +101,7 @@ public function overview() {
             '#content' => $this->systemManager->getAdminBlock($item),
           );
 
-          if (!empty($block['content'])) {
+          if (!empty($block['content']['#content'])) {
             $block['show'] = TRUE;
           }