Initial Drupal 11 with DDEV setup

web/core/modules/media/src/IFrameMarkup.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Drupal\media;
+
+use Drupal\Component\Render\MarkupInterface;
+use Drupal\Component\Render\MarkupTrait;
+
+/**
+ * Defines an object that wraps oEmbed markup for use in an iFrame.
+ *
+ * This object is not constructed with a known safe string as the strings come
+ * from an external site. It must not be used outside the Media module's oEmbed
+ * iframe rendering.
+ *
+ * @internal
+ *   This object is an internal part of the oEmbed system and should only be
+ *   used in \Drupal\media\Controller\OEmbedIframeController.
+ *
+ * @see \Drupal\media\Controller\OEmbedIframeController
+ */
+class IFrameMarkup implements MarkupInterface {
+  use MarkupTrait;
+
+}