WordPress at a glance
action is not described

wp_logout action-hook . WP 1.5.0

Fires after a user is logged out.

Usage

add_action( 'wp_logout', 'action_function_name_8323' );
function action_function_name_8323( $user_id ){
	// action...
}
$user_id(int)
ID of the user that was logged out.

Changelog

Since 1.5.0 Introduced.
Since 5.5.0 Added the $user_id parameter.

Where the hook is called

wp_logout()
wp_logout
wp-includes/pluggable.php 600
do_action( 'wp_logout', $user_id );

Where in WP core the hook is used WordPress

wp-includes/pluggable.php 94
add_action( 'wp_logout', array( $this, 'exit_recovery_mode' ) );