All classes that implement ExtraFieldFormInterface in Extra Field 8.2

class \Drupal\extra_field\Plugin\ExtraFieldFormBase implements ExtraFieldFormInterface uses StringTranslationTrait
class \Drupal\extra_field_example\Plugin\ExtraField\Form\CustomSubmit uses MessengerTrait
class \Drupal\extra_field_example\Plugin\ExtraField\Form\ExampleCustomInput implements ContainerFactoryPluginInterface uses StringTranslationTrait
class \Drupal\extra_field_example\Plugin\ExtraField\Form\ExampleMarkup
class \Drupal\extra_field_test\Plugin\ExtraField\Form\SingleItemTest

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