diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 7418b49..3ed3ae5 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2275,7 +2275,7 @@ function theme_tablesort_indicator($variables) {
 /**
  * Prepares variables for mark templates.
  *
- * Default template: mark.html.twig
+ * Default template: mark.html.twig.
  *
  * @param array $variables
  *   An associative array containing:
@@ -2288,8 +2288,6 @@ function template_preprocess_mark(&$variables) {
   if ($user->uid) {
     $variables['logged_in'] = TRUE;
   }
-  $variables['MARK_NEW'] = MARK_NEW;
-  $variables['MARK_UPDATED'] = MARK_UPDATED;
 }
 
 /**
diff --git a/core/modules/system/templates/mark.html.twig b/core/modules/system/templates/mark.html.twig
index 2008222..72254b7 100644
--- a/core/modules/system/templates/mark.html.twig
+++ b/core/modules/system/templates/mark.html.twig
@@ -4,8 +4,11 @@
  * Default theme implementation for a marker for new or updated content.
  *
  * Available variables:
- * - type: Number representing the marker type to display. See MARK_NEW,
- *    MARK_UPDATED, MARK_READ.
+ * - type: Number representing the marker type to display. Use the constants
+ *   below for comparison:
+ *   - MARK_NEW
+ *   - MARK_UPDATED
+ *   - MARK_READ
  * - logged_in: TRUE if the user is logged in, else FALSE.
  *
  * @see template_preprocess()
@@ -15,9 +18,9 @@
  */
 #}
 {% if logged_in %}
-  {% if type == MARK_NEW %}
+  {% if type is constant('MARK_NEW') %}
     <span class="marker">{{ 'new'|t }}</span>
-  {% elseif type == MARK_UPDATED %}
+  {% elseif type is constant('MARK_UPDATED') %}
     <span class="marker">{{ 'updated'|t }}</span>
   {% endif %}
 {% endif %}