diff --git a/core/modules/aggregator/templates/aggregator-feed.html.twig b/core/modules/aggregator/templates/aggregator-feed.html.twig
index ee44c35..42b02ac 100644
--- a/core/modules/aggregator/templates/aggregator-feed.html.twig
+++ b/core/modules/aggregator/templates/aggregator-feed.html.twig
@@ -12,6 +12,12 @@
  *   or print a subset such as {{ content.field_example }}. Use
  *   {{ content|without('field_example') }} to temporarily suppress the printing
  *   of a given element.
+ * - title_attributes: Same as attributes, except applied to the main title
+ *   tag that appears in the template.
+ * - title_prefix: Additional output populated by modules, intended to be
+ *   displayed in front of the main title tag that appears in the template.
+ * - title_suffix: Additional output populated by modules, intended to be
+ *   displayed after the main title tag that appears in the template.
  *
  * @see template_preprocess_aggregator_feed()
  *
diff --git a/core/modules/aggregator/templates/aggregator-item.html.twig b/core/modules/aggregator/templates/aggregator-item.html.twig
index 2391ad8..a907aa5 100644
--- a/core/modules/aggregator/templates/aggregator-item.html.twig
+++ b/core/modules/aggregator/templates/aggregator-item.html.twig
@@ -10,6 +10,11 @@
  *   or print a subset such as {{ content.field_example }}. Use
  *   {{ content|without('field_example') }} to temporarily suppress the printing
  *   of a given element.
+ * - attributes: HTML attributes for the wrapper.
+ * - title_prefix: Additional output populated by modules, intended to be
+ *   displayed in front of the main title tag that appears in the template.
+ * - title_suffix: Additional output populated by modules, intended to be
+ *   displayed after the main title tag that appears in the template.
  *
  * @see template_preprocess_aggregator_item()
  *
diff --git a/core/themes/classy/templates/content/aggregator-item.html.twig b/core/themes/classy/templates/content/aggregator-item.html.twig
index 20f6d7c..83ef5d0 100644
--- a/core/themes/classy/templates/content/aggregator-item.html.twig
+++ b/core/themes/classy/templates/content/aggregator-item.html.twig
@@ -10,6 +10,11 @@
  *   or print a subset such as {{ content.field_example }}. Use
  *   {{ content|without('field_example') }} to temporarily suppress the printing
  *   of a given element.
+ * - attributes: HTML attributes for the wrapper.
+ * - title_prefix: Additional output populated by modules, intended to be
+ *   displayed in front of the main title tag that appears in the template.
+ * - title_suffix: Additional output populated by modules, intended to be
+ *   displayed after the main title tag that appears in the template.
  *
  * @see template_preprocess_aggregator_item()
  */
diff --git a/core/themes/classy/templates/dataset/aggregator-feed.html.twig b/core/themes/classy/templates/dataset/aggregator-feed.html.twig
index 9153a52..9b1229a 100644
--- a/core/themes/classy/templates/dataset/aggregator-feed.html.twig
+++ b/core/themes/classy/templates/dataset/aggregator-feed.html.twig
@@ -12,6 +12,13 @@
  *   or print a subset such as {{ content.field_example }}. Use
  *   {{ content|without('field_example') }} to temporarily suppress the printing
  *   of a given element.
+ * - attributes: HTML attributes for the wrapper.
+ * - title_attributes: Same as attributes, except applied to the main title
+ *   tag that appears in the template.
+ * - title_prefix: Additional output populated by modules, intended to be
+ *   displayed in front of the main title tag that appears in the template.
+ * - title_suffix: Additional output populated by modules, intended to be
+ *   displayed after the main title tag that appears in the template.
  *
  * @see template_preprocess_aggregator_feed()
  */
diff --git a/core/themes/stable/templates/content/aggregator-item.html.twig b/core/themes/stable/templates/content/aggregator-item.html.twig
index f60bdde..96dd420 100644
--- a/core/themes/stable/templates/content/aggregator-item.html.twig
+++ b/core/themes/stable/templates/content/aggregator-item.html.twig
@@ -10,6 +10,11 @@
  *   or print a subset such as {{ content.field_example }}. Use
  *   {{ content|without('field_example') }} to temporarily suppress the printing
  *   of a given element.
+ * - attributes: HTML attributes for the wrapper.
+ * - title_prefix: Additional output populated by modules, intended to be
+ *   displayed in front of the main title tag that appears in the template.
+ * - title_suffix: Additional output populated by modules, intended to be
+ *   displayed after the main title tag that appears in the template.
  *
  * @see template_preprocess_aggregator_item()
  */
diff --git a/core/themes/stable/templates/dataset/aggregator-feed.html.twig b/core/themes/stable/templates/dataset/aggregator-feed.html.twig
index 7ad0790..0307af8 100644
--- a/core/themes/stable/templates/dataset/aggregator-feed.html.twig
+++ b/core/themes/stable/templates/dataset/aggregator-feed.html.twig
@@ -12,6 +12,12 @@
  *   or print a subset such as {{ content.field_example }}. Use
  *   {{ content|without('field_example') }} to temporarily suppress the printing
  *   of a given element.
+ * - title_attributes: Same as attributes, except applied to the main title
+ *   tag that appears in the template.
+ * - title_prefix: Additional output populated by modules, intended to be
+ *   displayed in front of the main title tag that appears in the template.
+ * - title_suffix: Additional output populated by modules, intended to be
+ *   displayed after the main title tag that appears in the template.
  *
  * @see template_preprocess_aggregator_feed()
  */