tml_logout_handler()

function tml_logout_handler() {

    check_admin_referer( 'log-out' );

    $user = wp_get_current_user();

    wp_logout();

    if ( ! empty( $_REQUEST['redirect_to'] ) ) {
        $redirect_to           = $_REQUEST['redirect_to'];
        $requested_redirect_to = $redirect_to;
    } else {
        $redirect_to           = add_query_arg(
            array(
                'loggedout' => 'true',
                'wp_lang'   => get_user_locale( $user ),
            ),
            wp_login_url()
        );
        $requested_redirect_to = '';
    }

    /** This filter is documented in wp-login.php */
    $redirect_to = apply_filters( 'logout_redirect', $redirect_to, $requested_redirect_to, $user );

    wp_safe_redirect( $redirect_to );
    exit;
}

View src/includes/actions.php, line 609 on GitHub