где хранятся значения FORM_ERRORS_TEXT?

...
if ($arResult["isFormErrors"] == "Y")
{
   ob_start();
   if ($arParams['USE_EXTENDED_ERRORS'] == 'N' || !is_array($arResult['FORM_ERRORS']))
      ShowError($arResult["FORM_ERRORS"]);
   else
      ShowError(implode('<br />', $arResult["FORM_ERRORS"]));

   $arResult["FORM_ERRORS_TEXT"] = ob_get_contents();
   ob_end_clean();
}
...