woocommerce_order_item_add_action_buttons │ action-hook │ WC 1.0

Usage

add_action( 'woocommerce_order_item_add_action_buttons', 'wp_kama_woocommerce_order_item_add_action_buttons_action' );

/**
 * Function for `woocommerce_order_item_add_action_buttons` action-hook.
 * 
 * @param  $order 
 *
 * @return void
 */
function wp_kama_woocommerce_order_item_add_action_buttons_action( $order ){

	// action...
}

$order

-

Where the hook is called

do_action( 'woocommerce_order_item_add_action_buttons', $order );

Where the hook is used in WooCommerce