memo property
Optional human-readable memo to seed the (editable) memo field. Only a TEXT memo is representable in the editable field; a machine (ZIP-302 0xFF) or reserved memo carried by a URI is rejected typed at fromUri rather than silently dropped (a payment-reference the recipient may need must not vanish). A memo to a transparent recipient is still dropped at compose by the existing send-form gate — a prefill does not bypass that.
Implementation
final String? memo;