WordPress at a glance
filter is not described

woocommerce_order_is_vat_exempt filter-hook . WC 1.0

Usage

add_filter( 'woocommerce_order_is_vat_exempt', 'filter_function_name_4156', 10, 2 );
function filter_function_name_4156( $string, $that ){
	// filter...

	return $string;
}
$string
-
$that
-

Where the hook is called

WC_Abstract_Order::calculate_taxes()
woocommerce_order_is_vat_exempt
woocommerce/includes/abstracts/abstract-wc-order.php 1415
$is_vat_exempt = apply_filters( 'woocommerce_order_is_vat_exempt', 'yes' === $this->get_meta( 'is_vat_exempt' ), $this );

Where the hook is used (in WC core)

Usage not found!