diff --git a/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php b/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php
index 5935da5..4133d42 100644
--- a/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php
+++ b/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php
@@ -721,10 +721,11 @@ protected function buildXPathQuery($xpath, array $args = []) {
   /**
    * Gets the current raw content.
    *
-   * @deprecated in Drupal 8.4.0 and will be removed before Drupal 9.0.0.
+   * @deprecated Scheduled for removal in Drupal 9.0.0.
    *   Use $this->getSession()->getPage()->getContent() instead.
    */
   protected function getRawContent() {
+    @trigger_error('AssertLegacyTrait::getRawContent() is scheduled for removal in Drupal 9.0.0. Use $this->assertSession()->buildXPathQuery() instead.', E_USER_DEPRECATED);
     return $this->getSession()->getPage()->getContent();
   }