WordPress at a glance
function is not described

PHPMailer\PHPMailer

SMTP::setDebugOutput() public WP 1.0

Set debug output method.

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

No Hooks.

Return

null. Nothing.

Usage

$SMTP = new SMTP();
$SMTP->setDebugOutput( $method );
$method(string|callable)
The name of the mechanism to use for debugging output, or a callable to handle it

Code of SMTP::setDebugOutput() WP 5.7.2

<?php
public function setDebugOutput($method = 'echo')
{
    $this->Debugoutput = $method;
}