Expanded class hierarchy of FormElementInterface in Drupal 9
- interface \Drupal\Component\Plugin\PluginInspectionInterface; interface \Drupal\Core\Render\Element\RenderCallbackInterface
- interface \Drupal\Core\Render\Element\ElementInterface
- interface \Drupal\Core\Render\Element\FormElementInterface
- interface \Drupal\Core\Render\Element\ElementInterface