code: public function getFieldConfiguration()
      {
          $pageType = ($this->getSetting('PageTypeName')) ? $this->getSetting('PageTypeName') : 0;
          // Get all subclasses of Page class
          $allTypes = ClassInfo::subclassesFor('Page');
  
          // Create sorted array with keys and values are class names
          $types = [];
          foreach ($allTypes as $type) {
              $types[(string) $type] = Page::create_from_string($type)->singular_name();
          }
          asort($types);
  
          return [
              new DropdownField(
                  $this->getSettingName('PageTypeName'),
                  _t('Moo_EditableFieldPageTypeList.PAGETYPENAME', 'Page Type Name'),
                  $types,
                  $pageType
              ),
          ];
      }
docs: Get extra configuration fields.
  
  @return array