code: public function submitForm(array &$form, FormStateInterface $form_state) {
      // The revision timestamp will be updated when the revision is saved. Keep
      // the original one for the confirmation message.
      $original_revision_timestamp = $this->revision->getRevisionCreationTime();
  
      $this->revision = $this->prepareRevertedRevision($this->revision, $form_state);
      $this->revision->revision_log = t('Copy of the revision from %date.', ['%date' => $this->dateFormatter->format($original_revision_timestamp)]);
      $this->revision->setRevisionUserId($this->currentUser()->id());
      $this->revision->setRevisionCreationTime($this->time->getRequestTime());
      $this->revision->setChangedTime($this->time->getRequestTime());
      $this->revision->save();
  
      $this->logger('content')
        ->notice('@type: reverted %title revision %revision.', [
          '@type' => $this->revision->bundle(),
          '%title' => $this->revision->label(),
          '%revision' => $this->revision->getRevisionId(),
        ]);
      $this->messenger()
        ->addStatus($this->t('@type %title has been reverted to the revision from %revision-date.', [
          '@type' => node_get_type_label($this->revision),
          '%title' => $this->revision->label(),
          '%revision-date' => $this->dateFormatter->format($original_revision_timestamp),
        ]));
      $form_state->setRedirectUrl($this->getCancelUrl());
    }
docs: {@inheritdoc}