reverted:
--- b/core/modules/contextual/src/Element/ContextualLinksPlaceholder.php
+++ a/core/modules/contextual/src/Element/ContextualLinksPlaceholder.php
@@ -47,8 +47,7 @@
    * @see _contextual_links_to_id()
    */
   public static function preRenderPlaceholder(array $element) {
+    $element['#markup'] = '<div' . new Attribute(array('data-contextual-id' => $element['#id'])) . '></div>';
-    // @todo Consider String::format instead.
-    $element['#markup'] = SafeMarkup::set('<div' . new Attribute(array('data-contextual-id' => $element['#id'])) . '></div>');
     return $element;
   }
 
only in patch2:
unchanged:
--- a/core/modules/filter/src/Element/ProcessedText.php
+++ b/core/modules/filter/src/Element/ProcessedText.php
@@ -8,6 +8,7 @@
 namespace Drupal\filter\Element;
 
 use Drupal\Component\Utility\NestedArray;
+use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Render\BubbleableMetadata;
 use Drupal\Core\Render\Element\RenderElement;
@@ -120,7 +121,7 @@ public static function preRenderText($element) {
 
     // Filtering done, store in #markup, set the updated bubbleable rendering
     // metadata, and set the text format's cache tag.
-    $element['#markup'] = $text;
+    $element['#markup'] = SafeMarkup::set($text);
     $metadata->applyTo($element);
     $element['#cache']['tags'] = Cache::mergeTags($element['#cache']['tags'], $format->getCacheTags());