WordPress at a glance
action is not described

pre_user_search action-hook . WP 1.0

Usage

add_action( 'pre_user_search', 'action_function_name_2069' );
function action_function_name_2069( &$this ){
	// action...
}
&$this
-

Where the hook is called

WP_User_Search::prepare_query()
wp-admin/includes/deprecated.php 552
do_action_ref_array( 'pre_user_search', array( &$this ) );

Where the hook is used (in WP core)

Does not used.