diff --git a/core/modules/system/templates/pager.html.twig b/core/modules/system/templates/pager.html.twig
index 43d5b4c..7ab5a83 100644
--- a/core/modules/system/templates/pager.html.twig
+++ b/core/modules/system/templates/pager.html.twig
@@ -20,10 +20,13 @@
  *     - attributes: A keyed list of HTML attributes for the item.
  *     - text: The visible text used for the item link, such as "‹ previous"
  *       or "next ›".
-
+ *
  * - current: The page number of the current page.
  * - ellipses: If there are more pages than the quantity allows, then an
  *   ellipsis before or after the listed pages may be present.
+ *   - previous: Present if the currently visible list of pages does not start
+ *     at the first page.
+ *   - next: Present if the visibile list of pages ends before the last page.
  *
  * @see template_preprocess_pager()
  *