Details about the application that took the payment.
The Square product, such as Square Point of Sale (POS), Square Invoices, or Square Virtual Terminal.
The Square ID assigned to the application used to take the payment. Application developers can use this information to identify payments that their application processed. For example, if a developer uses a custom application to process payments, this field contains the application ID from the Developer Dashboard. If a seller uses a Square App Marketplace application to process payments, the field contains the corresponding application ID.