diff -u b/core/modules/rdf/templates/rdf-metadata.html.twig b/core/modules/rdf/templates/rdf-metadata.html.twig
--- b/core/modules/rdf/templates/rdf-metadata.html.twig
+++ b/core/modules/rdf/templates/rdf-metadata.html.twig
@@ -20,3 +20,3 @@
 {% for attributes in metadata %}
-  <span{{ attributes }}></span>
+  <span{{ attributes.addClass('hidden') }}></span>
 {% endfor %}
reverted:
--- b/core/themes/classy/templates/rdf-metadata.html.twig
+++ /dev/null
@@ -1,22 +0,0 @@
-{#
-/**
- * @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.
- *
- * @see template_preprocess_rdf_metadata()
- *
- * @ingroup themeable
- */
-#}
-{% for attributes in metadata %}
-  <span{{ attributes.addClass('rdf-meta', 'hidden') }}></span>
-{% endfor %}