WordPress at a glance
action is not described

network_site_new_created_user action-hook . WP 4.4.0

Fires after a new user has been created via the network site-new.php page.

Usage

add_action( 'network_site_new_created_user', 'action_function_name_1065' );
function action_function_name_1065( $user_id ){
	// action...
}
$user_id(int)
ID of the newly created user.

Where the hook is called

In file: /wp-admin/network/site-new.php
network_site_new_created_user
wp-admin/network/site-new.php 128
do_action( 'network_site_new_created_user', $user_id );

Where the hook is used (in WP core)

wp-includes/ms-default-filters.php 30
add_action( 'network_site_new_created_user', 'wp_send_new_user_notifications' );