getRegionLabels example

$storage_type = $section_storage->getStorageType();
    $storage_id = $section_storage->getStorageId();
    $section = $section_storage->getSection($delta);

    $layout = $section->getLayout($this->getPopulatedContexts($section_storage));
    $layout_settings = $section->getLayoutSettings();
    $section_label = !empty($layout_settings['label']) ? $layout_settings['label'] : $this->t('Section @section', ['@section' => $delta + 1]);

    $build = $section->toRenderArray($this->getPopulatedContexts($section_storage), TRUE);
    $layout_definition = $layout->getPluginDefinition();

    $region_labels = $layout_definition->getRegionLabels();
    foreach ($layout_definition->getRegions() as $region => $info) {
      if (!empty($build[$region])) {
        foreach (Element::children($build[$region]) as $uuid) {
          $build[$region][$uuid]['#attributes']['class'][] = 'js-layout-builder-block';
          $build[$region][$uuid]['#attributes']['class'][] = 'layout-builder-block';
          $build[$region][$uuid]['#attributes']['data-layout-block-uuid'] = $uuid;
          $build[$region][$uuid]['#attributes']['data-layout-builder-highlight-id'] = $this->blockUpdateHighlightId($uuid);
          $build[$region][$uuid]['#contextual_links'] = [
            'layout_builder_block' => [
              'route_parameters' => [
                'section_storage_type' => $storage_type,