pageFeedDisplayOptions example

'sorts' => [],
    ];
    $display_options['default']['filters'] += $this->defaultDisplayFilters($form, $form_state);
    $display_options['default']['sorts'] += $this->defaultDisplaySorts($form, $form_state);

    // Display: Page     if (!$form_state->isValueEmpty(['page', 'create'])) {
      $display_options['page'] = $this->pageDisplayOptions($form, $form_state);

      // Display: Feed (attached to the page)       if (!$form_state->isValueEmpty(['page', 'feed'])) {
        $display_options['feed'] = $this->pageFeedDisplayOptions($form, $form_state);
      }
    }

    // Display: Block     if (!$form_state->isValueEmpty(['block', 'create'])) {
      $display_options['block'] = $this->blockDisplayOptions($form, $form_state);
    }

    // Display: REST export.     if (!$form_state->isValueEmpty(['rest_export', 'create'])) {
      $display_options['rest_export'] = $this->restExportDisplayOptions($form, $form_state);
    }