During December 2024, Kyungjun Lee developed comprehensive documentation for Kafka consumer group rebalancing within the kyungjunleeme/kafka_study repository. Focusing on distributed systems and leveraging expertise in Kafka and Markdown, Kyungjun clarified the mechanics of eager and cooperative rebalancing, detailed the roles of the Group Coordinator and Consumer Leader, and explained static group membership and configuration settings. The documentation also addressed offset management strategies and rebalance listener behavior, providing practical guidance for both automatic and manual commit scenarios. This work improved onboarding and knowledge transfer, reducing misconfiguration risks and troubleshooting time by making complex Kafka consumer behaviors more accessible and explicit.