diff --git a/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php b/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php
index 18a4d53..08a2d8e 100644
--- a/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php
+++ b/core/tests/Drupal/FunctionalTests/AssertLegacyTrait.php
@@ -736,19 +736,6 @@ protected function assertNoCacheTag($cache_tag) {
   }
 
   /**
-   * Asserts whether an expected cache tag was absent in the last response.
-   *
-   * @param string $cache_tag
-   *   The expected cache tag.
-   *
-   * @deprecated Scheduled for removal in Drupal 9.0.0.
-   *   Use $this->assertSession()->responseHeaderNotContains() instead.
-   */
-  protected function assertNoCacheTag($cache_tag) {
-    $this->assertSession()->responseHeaderNotContains('X-Drupal-Cache-Tags', $cache_tag);
-  }
-
-  /**
    * Checks that current response header equals value.
    *
    * @param string $name