woocommerce_layered_nav_default_query_type filter-hook . WC 1.0

Usage

add_filter( 'woocommerce_layered_nav_default_query_type', 'filter_function_name_7327' );
function filter_function_name_7327( $string ){
	// filter...

	return $string;
}

$string

-

Where the hook is called

self::$chosen_attributes[ $taxonomy ]['query_type'] = $query_type ? $query_type : apply_filters( 'woocommerce_layered_nav_default_query_type', 'and' );

Where in WP core the hook is used WooCommerce