Bundle v1

The raw schema is authoritative. A Bundle contains Chain v1 plus external asset manifests with ID, reference, SHA-256, byte length, and ETA1 format. Python Bundle.pack() and effetune bundle pack write this directory layout; JavaScript encodeEta1() writes canonical ETA1 bytes for resolvers. The resolver verifies hash, size, rate, channel, topology, and cross-field rules before processing. ZIP containers are outside v1.