17 files declare their use of FormBuilderInterface in Zircon Profile 8.0

AdminController.php in core/modules/comment/src/Controller/AdminController.php

Contains \Drupal\comment\Controller\AdminController.

AjaxFormBlock.php in core/modules/system/tests/modules/ajax_forms_test/src/Plugin/Block/AjaxFormBlock.php

Contains \Drupal\ajax_forms_test\Plugin\Block\AjaxFormBlock.

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

Contains \Drupal\system\Tests\Ajax\AjaxFormCacheTest.

BlockListBuilder.php in core/modules/block/src/BlockListBuilder.php

Contains \Drupal\block\BlockListBuilder.

DbLogController.php in core/modules/dblog/src/Controller/DbLogController.php

Contains \Drupal\dblog\Controller\DbLogController.

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

Contains \Drupal\system\Tests\Ajax\DialogTest.

EntityFormBuilder.php in core/lib/Drupal/Core/Entity/EntityFormBuilder.php

Contains \Drupal\Core\Entity\EntityFormBuilder.

FormAjaxSubscriber.php in core/lib/Drupal/Core/Form/EventSubscriber/FormAjaxSubscriber.php

Contains \Drupal\Core\Form\EventSubscriber\FormAjaxSubscriber.

FormAjaxSubscriberTest.php in core/tests/Drupal/Tests/Core/Form/EventSubscriber/FormAjaxSubscriberTest.php

Contains \Drupal\Tests\Core\Form\EventSubscriber\FormAjaxSubscriberTest.

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

Contains \Drupal\Tests\Core\Form\FormBuilderTest.

FormController.php in core/lib/Drupal/Core/Controller/FormController.php

Contains \Drupal\Core\Controller\FormController.

HtmlEntityFormController.php in core/lib/Drupal/Core/Entity/HtmlEntityFormController.php

Contains \Drupal\Core\Entity\HtmlEntityFormController.

HtmlFormController.php in core/lib/Drupal/Core/Controller/HtmlFormController.php

Contains \Drupal\Core\Controller\HtmlFormController.

RedirectFormBlock.php in core/modules/system/tests/modules/form_test/src/Plugin/Block/RedirectFormBlock.php

Contains \Drupal\form_test\Plugin\Block\RedirectFormBlock.

RenderElement.php in core/lib/Drupal/Core/Render/Element/RenderElement.php

Contains \Drupal\Core\Render\Element\RenderElement.

RenderElementTest.php in core/tests/Drupal/Tests/Core/Render/Element/RenderElementTest.php

Contains \Drupal\Tests\Core\Render\Element\RenderElementTest.

SystemController.php in core/modules/system/src/Controller/SystemController.php

Contains \Drupal\system\Controller\SystemController.