During December 2025, Christian Birk worked on the nrfconnect/sdk-zephyr repository, focusing on improving the documentation for Zbus channel observer priority parameters. He clarified the descriptions of the _observers parameter in both ZBUS_CHAN_DEFINE and ZBUS_CHAN_DEFINE_WITH_ID, addressing spelling and grammar issues to enhance readability and reduce ambiguity for developers. The work was documentation-only, ensuring API compatibility while supporting better onboarding and day-to-day usage. Using his skills in C programming, embedded systems, and technical documentation, Christian maintained clear commit traceability, reinforcing maintainability and knowledge transfer within the codebase without introducing new features or altering existing functionality.