carriesSignature

Returns whether signature carries a signature payload rather than an unsigned placeholder.

SCValTypeXdr.SCV_VOID and SCValXdr.Vec values with a null or empty inner vector are unsigned; every other value carries a signature. This follows js-stellar-sdk v17.2.1: auth.ts lines 482 to 487 writes an empty-vector placeholder, and signaturePresent, lines 1108 to 1121 treats it like void.

This classifies placeholders; it does not judge whether an empty vector authorizes a custom account contract. Such a payload is reported as unsigned even when that contract accepts it.