counterpartyMarker property
The app's opaque marker for the counterparty of this payment (bead libspiffy-cq16, spv-understanding.md "Core Data Management" requirement 5): an Ed25519 identity key, an email address, a peer id, an internal account id — whatever the app uses for identity. It is stored with the payment and returned by the transaction queries; libspiffy never interprets, validates or parses it, and the identity record itself stays with the app. Null when none is supplied.
Implementation
final String? counterpartyMarker;