6 files declare their use of AlertCommand in Zircon Profile 8

AjaxCommandsTest.php in core/tests/Drupal/Tests/Core/Ajax/AjaxCommandsTest.php

Contains \Drupal\Tests\Core\Ajax\AjaxCommandsTest.

AjaxRenderer.php in core/lib/Drupal/Core/Render/MainContent/AjaxRenderer.php

Contains \Drupal\Core\Render\MainContent\AjaxRenderer.

AjaxTestController.php in core/modules/system/tests/modules/ajax_test/src/Controller/AjaxTestController.php

Contains \Drupal\ajax_test\Controller\AjaxTestController.

CommandsTest.php in core/modules/system/src/Tests/Ajax/CommandsTest.php

Contains \Drupal\system\Tests\Ajax\CommandsTest.

FormAjaxResponseBuilderTest.php in core/tests/Drupal/Tests/Core/Form/FormAjaxResponseBuilderTest.php

Contains \Drupal\Tests\Core\Form\FormAjaxResponseBuilderTest.

FrameworkTest.php in core/modules/system/src/Tests/Ajax/FrameworkTest.php

Contains \Drupal\system\Tests\Ajax\FrameworkTest.