a1c47b6d_ation__NVP____PayPal_Developer__Field
[Description] (Optional) Unique ID passed for each API request to help prevent duplicate payments. This ID is passed directly back in the response. For more information, see Idempotency. Character length and limitations: 38 single-byte characters maximum. Added in version 114 of the API. [Field] 
MSGSUBID
DoExpressCheckoutPayment API Operation (NVP) - PayPal Developer
Field