WordPress at a glance
filter is not described

woocommerce_countries_shipping_countries filter-hook . WC 1.0

Usage

add_filter( 'woocommerce_countries_shipping_countries', 'filter_function_name_1763' );
function filter_function_name_1763( $countries ){
	// filter...

	return $countries;
}
$countries
-

Where the hook is called

WC_Countries::get_shipping_countries()
woocommerce_countries_shipping_countries
woocommerce/includes/class-wc-countries.php 304
return apply_filters( 'woocommerce_countries_shipping_countries', $countries );

Where in WP core the hook is used WooCommerce

Usage not found.