Worked on the Kotlin/kotlinx.serialization repository to deliver ProtoBuf support for Kotlin unsigned types, specifically UByteArray and UInt. This involved implementing encoding and decoding changes to handle packed unsigned encoding, ensuring correct serialization and deserialization of these types. The approach included expanding test coverage to validate edge cases and maintain regression safety, thereby improving reliability for projects relying on ProtoBuf serialization. Utilized Kotlin as the primary language, with a focus on serialization and comprehensive testing practices. The work addressed issues with ProtoBuf packing for unsigned types, enhancing data integrity and correctness in the serialization process for Kotlin applications.