Worked on the libsdl-org/libavif repository to deliver support for embedding custom image properties into AVIF images during encoding. Developed new C APIs, avifImageAddOpaqueProperty and avifImageAddUUIDProperty, enabling the addition of non-standard metadata to AVIF files and expanding downstream metadata workflows. The implementation included detailed validation checks and comprehensive unit tests to ensure correct handling of custom properties. Focused on maintainable API design and thorough documentation, the work leveraged skills in C programming, file format specification, and image encoding. No major bugs were addressed during this period, with efforts concentrated on feature development and robust test coverage.