woocommerce_attribute_default_visibility filter-hook . WC 1.0

Usage

add_filter( 'woocommerce_attribute_default_visibility', 'filter_function_name_902' );
function filter_function_name_902( $1 ){
	// filter...

	return $1;
}

$1

-

Where the hook is called

$attribute->set_visible( apply_filters( 'woocommerce_attribute_default_visibility', 1 ) );

Where in WP core the hook is used WooCommerce