WordPress at a glance
action is not described

manage_users_extra_tablenav action-hook . WP 4.9.0

Fires immediately following the closing "actions" div in the tablenav for the users list table.

Usage

add_action( 'manage_users_extra_tablenav', 'action_function_name_2572' );
function action_function_name_2572( $which ){
	// action...
}
$which(string)
The location of the extra table nav markup: 'top' or 'bottom'.

Where the hook is called

WP_Users_List_Table::extra_tablenav()
manage_users_extra_tablenav
wp-admin/includes/class-wp-users-list-table.php 287
do_action( 'manage_users_extra_tablenav', $which );

Where the hook is used (in WP core)

Does not used.