diff --git a/core/modules/rdf/rdf.module b/core/modules/rdf/rdf.module
index c6c6d1a..dc408b2 100644
--- a/core/modules/rdf/rdf.module
+++ b/core/modules/rdf/rdf.module
@@ -571,10 +571,6 @@ function template_preprocess_rdf_metadata(&$variables) {
     // are empty <span> tags in the document.
     $attributes['class'][] = 'rdf-meta';
     $attributes['class'][] = 'hidden';
-    // The XHTML+RDFa doctype allows either <span></span> or <span /> syntax to
-    // be used, but for maximum browser compatibility, W3C recommends the
-    // former when serving pages using the text/html media type, see
-    // http://www.w3.org/TR/xhtml1/#C_3.
     $variables['metadata'][$key] = new Attribute($attributes);
   }
 }
diff --git a/core/modules/rdf/templates/rdf-metadata.html.twig b/core/modules/rdf/templates/rdf-metadata.html.twig
index 81a2f3c..0a75fa9 100644
--- a/core/modules/rdf/templates/rdf-metadata.html.twig
+++ b/core/modules/rdf/templates/rdf-metadata.html.twig
@@ -3,6 +3,11 @@
  * @file
  * Default theme implementation for empty spans with RDF attributes.
  *
+ * The XHTML+RDFa doctype allows either <span></span> or <span /> syntax to
+ * be used, but for maximum browser compatibility, W3C recommends the
+ * former when serving pages using the text/html media type, see
+ * http://www.w3.org/TR/xhtml1/#C_3.
+ *
  * Available variables:
  * - metadata: Each item within corresponds to its own set of attributes,
  *   and therefore, needs its own 'attributes' element.