code: private function buildErrorList()
      {
          $errorStr = '';
          $errors = $this->debug->errorHandler->get('errors');
          \uasort($errors, function ($a1, $a2) {
              return \strcmp($a1['file'].$a1['line'], $a2['file'].$a2['line']);
          });
          $lastFile = '';
          foreach ($errors as $error) {
              if ($error['isSuppressed']) {
                  continue;
              }
              if ($error['file'] !== $lastFile) {
                  $errorStr .= $error['file'].':'."\n";
                  $lastFile = $error['file'];
              }
              $typeStr = $error['type'] === E_STRICT
                  ? 'Strict'
                  : $error['typeStr'];
              $errorStr .= '  Line '.$error['line'].': ('.$typeStr.') '.$error['message']."\n";
          }
          return $errorStr;
      }
docs: Build list of errors for email
  
  @return string