WordPress at a glance
function is not described

PHPMailer\PHPMailer

PHPMailer::rfcDate() public WP 1.0

Return an RFC 822 formatted date.

{} It's a method of the class: PHPMailer{}

No Hooks.

Return

String.

Usage

$result = PHPMailer::rfcDate();

Code of PHPMailer::rfcDate() WP 5.7.2

<?php
public static function rfcDate()
{
    //Set the time zone to whatever the default is to avoid 500 errors
    //Will default to UTC if it's not set properly in php.ini
    date_default_timezone_set(@date_default_timezone_get());

    return date('D, j M Y H:i:s O');
}