code: public static function getLibXmlLoaderOptions()
      {
          if (self::$libXmlLoaderOptions === null && defined('LIBXML_DTDLOAD')) {
              self::setLibXmlLoaderOptions(LIBXML_DTDLOAD | LIBXML_DTDATTR);
          } elseif (self::$libXmlLoaderOptions === null) {
              self::$libXmlLoaderOptions = true;
          }
  
          return self::$libXmlLoaderOptions;
      }
docs: Get default options for libxml loader.
  Defaults to LIBXML_DTDLOAD | LIBXML_DTDATTR when not set explicitly.
  
  @return int Default options for libxml loader