Transactional mailing: Value to replace

Transactional mailing: Value to replace.

• Enter value to replace specified key.
• Use <?php ?> or <?= ?> to enable PHP code support.
• Use <?= $event->getRuntimeParam('someParamName') ?> to retrieve some runtime param of FrontendAction.
• Use <?= $recipient['email'] ?> to retrieve info about recipient (parsed from "Send To").
• Use <?= $data['...'] ?> to retrieve additional trigger info.
  Available keys: 'emailTemplate', 'sendFrom', 'sendTo' (parsed from current form).