PHPMailer\PHPMailer

PHPMailer::setBoundaries │ public │ WP 1.0

Set the boundaries to use for delimiting MIME parts. If you override this, ensure you set all 3 boundaries to unique values. The default boundaries include a "=_" sequence which cannot occur in quoted-printable bodies, as suggested by https://www.rfc-editor.org/rfc/rfc2045#section-6.7

Method of the class: PHPMailer{}

No Hooks.

Returns

null. Nothing (null).

Usage

$PHPMailer = new PHPMailer();
$PHPMailer->setBoundaries();

PHPMailer::setBoundaries() code WP 6.8.1

wp-includes/PHPMailer/PHPMailer.php 
public function setBoundaries()
{
    $this->uniqueid = $this->generateId();
    $this->boundary[1] = 'b1=_' . $this->uniqueid;
    $this->boundary[2] = 'b2=_' . $this->uniqueid;
    $this->boundary[3] = 'b3=_' . $this->uniqueid;
}