All classes that implement MessageNotifyUiSenderSettingsFormInterface in Message UI 8
- class \Drupal\message_notify_ui\MessageNotifyUiSenderSettingsFormBase implements MessageNotifyUiSenderSettingsFormInterface
- class \Drupal\message_notify_ui\Plugin\MessageNotifyUiSenderSettingsForm\MessageNotifyUiSenderMailSettingsForm implements MessageNotifyUiSenderSettingsFormInterface