During January 2026, this developer enhanced the contentauth/c2pa-rs repository by extending assertion metadata capabilities to support arbitrary key/value fields. They designed and implemented a robust set and get API in Rust, enabling clients to define custom metadata attributes beyond the standard schema. Comprehensive unit tests were developed to ensure correctness, regression safety, and schema compatibility, reflecting a disciplined approach to software development and API design. This work improved the extensibility and interoperability of C2PA assertions, reducing integration effort for downstream systems. Their contributions focused on API development, Rust programming, and thorough test coverage to maintain provenance integrity and client flexibility.