PHPMailer::addCustomHeader( string $name, string|null $value = null ): bool

4608    public function addCustomHeader($name, $value = null)4609    {4610        if (null === $value && strpos($name, ':') !== false) {4611            //Value passed in as name:value4612            list($name, $value) = explode(':', $name, 2);4613        }4614        $name = trim($name);4615        $value = (null === $value) ? '' : trim($value);4616        //Ensure name is not empty, and that neither name nor value contain line breaks4617        if (empty($name) || strpbrk($name . $value, "\r\n") !== false) {4618            if ($this->exceptions) {4619                throw new Exception(self::lang('invalid_header'));4620            }4621 4622            return false;4623        }4624        $this->CustomHeader[] = [$name, $value];4625 4626        return true;4627    }