wp-includes/PHPMailer/PHPMailer.php:4424Add an error message to the error container.
$msgstring protected function setError($msg) { ++$this->error_count; if ('smtp' === $this->Mailer && null !== $this->smtp) { $lasterror = $this->smtp->getError(); if (!empty($lasterror['error'])) { $msg .= ' ' . self::lang('smtp_error') . $lasterror['error']; if (!empty($lasterror['detail'])) { $msg .= ' ' . self::lang('smtp_detail') . $lasterror['detail']; } if (!empty($lasterror['smtp_code'])) { $msg .= ' ' . self::lang('smtp_code') . $lasterror['smtp_code']; } if (!empty($lasterror['smtp_code_ex'])) { $msg .= ' ' . self::lang('smtp_code_ex') . $lasterror['smtp_code_ex']; } } } $this->ErrorInfo = $msg; }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/PHPMailer/PHPMailer.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.