woocommerce_cancel_unpaid_order filter-hook . WC 1.0

Usage

add_filter( 'woocommerce_cancel_unpaid_order', 'filter_function_name_6406', 10, 2 );
function filter_function_name_6406( $string, $order ){
	// filter...

	return $string;
}

$string

-

$order

-

Where the hook is called

if ( apply_filters( 'woocommerce_cancel_unpaid_order', 'checkout' === $order->get_created_via(), $order ) ) {

Where in WP core the hook is used WooCommerce