File: //proc/thread-self/cwd/wp-includes/class-smtp.php
<?php
/**
* The SMTP class has been moved to the wp-includes/PHPMailer subdirectory and now uses the PHPMailer\PHPMailer namespace.
*/
_deprecated_file(
basename( __FILE__ ),
'5.5.0',
WPINC . '/PHPMailer/SMTP.php',
__( 'The SMTP class has been moved to the wp-includes/PHPMailer subdirectory and now uses the PHPMailer\PHPMailer namespace.' )
);
require_once __DIR__ . '/PHPMailer/SMTP.php';
class_alias( PHPMailer\PHPMailer\SMTP::class, 'SMTP' );