woocommerce_admin_order_item_types filter-hook . WC 1.0

Usage

add_filter( 'woocommerce_admin_order_item_types', 'filter_function_name_3535' );
function filter_function_name_3535( $string ){
	// filter...

	return $string;
}

$string

-

Where the hook is called

$line_items          = $order->get_items( apply_filters( 'woocommerce_admin_order_item_types', 'line_item' ) );

Where in WP core the hook is used WooCommerce