wp-includes/PHPMailer/SMTP.php:711Close the socket and clean up the state of the class.
public function close() { $this->server_caps = null; $this->helo_rply = null; if (is_resource($this->smtp_conn)) { //Close the connection and cleanup fclose($this->smtp_conn); $this->smtp_conn = null; //Makes for cleaner serialization $this->edebug('Connection: closed', self::DEBUG_CONNECTION); } }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/PHPMailer/SMTP.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.