OptionalamountOptionalcurrencyOptionalcustomer_OptionalenvironmentOptionalexternal_OptionalkindOptionalproduct_Optionalpurchased_OptionalquantityOptionalrefunded_OptionalskuOptionalstatusThe store's product id; on the web, your own code for what was bought.
The catalog product, by id or SKU (otherwise matched by the App Store / Google Play product id).