diff --git a/core/tests/Drupal/Tests/BrowserTestBase.php b/core/tests/Drupal/Tests/BrowserTestBase.php
index ba08cd5..64a2219 100644
--- a/core/tests/Drupal/Tests/BrowserTestBase.php
+++ b/core/tests/Drupal/Tests/BrowserTestBase.php
@@ -263,7 +263,9 @@
   /**
    * Mink session manager.
    *
-   * @var \Behat\Mink\Mink
+   * This will not be initialized if there was an error during the test setup.
+   *
+   * @var \Behat\Mink\Mink|null
    */
   protected $mink;