WordPress at a glance
filter is not described

autocomplete_users_for_site_admins filter-hook . WP 3.4.0

Filters whether to enable user auto-complete for non-super admins in Multisite.

Usage

add_filter( 'autocomplete_users_for_site_admins', 'filter_function_name_8250' );
function filter_function_name_8250( $enable ){
	// filter...

	return $enable;
}
$enable(true/false)
Whether to enable auto-complete for non-super admins.
Default: false

Where the hook is called

In file: /wp-admin/user-new.php
autocomplete_users_for_site_admins
wp-admin/user-new.php 235
&& ( current_user_can( 'manage_network_users' ) || apply_filters( 'autocomplete_users_for_site_admins', false ) )
wp-admin/includes/ajax-actions.php 249
if ( ! current_user_can( 'manage_network_users' ) && ! apply_filters( 'autocomplete_users_for_site_admins', false ) )

Where the hook is used (in WP core)

Does not used.