Symbious Digital Product Passport — GS1 Digital Link schema

Public reference schema for the Symbious™ Digital Product Passport: a GS1 Digital Link–addressed passport for a physical craft good (reference: natural cowhide leather), resolvable from an NFC tap or QR scan and carrying an append-only chain of custody. Defines the passport field set with per-field visibility (public / restricted), the GS1 Digital Link addressing pattern (AI 01 = GTIN, AI 21 = serial; one passport per item), and the provenance chain-of-custody structure (tanned → cut → assembled → finished → sold → repaired) recorded by role, never by named person. Published as an interoperability reference aligned with emerging Digital Product Passport requirements. This schema is the provenance expression of the infrastructure described in the position paper The Digital Membrane, and is governed by the Concordat. CC-BY 4.0.