Independent This document defines the SDLP lineage model, which provides the canonical method for representing the ancestry of SDLP-governed objects. Lineage is a structural property that records how an object evolves through duplication and transformation events. The lineage model ensures that descendant objects remain uniquely identifiable and traceable across all lifecycle transitions. Lineage-03 aligns the lineage grammar with Identity-02, Lifecycle-02, and Object-Format-07, and defines deterministic ancestry extension rules that produce stable, verifiable lineage across all SDLP implementations. This revision incorporates BitDrop conditions for invalid lineage transitions and specifies normative validation requirements for relying parties. Together with Identity-02, Lifecycle-02, and Object-Format-07, this document provides the authoritative lineage model required for interoperable identity, lifecycle, and provenance processing.