During September 2025, Dusan Mijic focused on improving the zio/zio repository by addressing a documentation bug related to running tagged tests via the command line. He identified that the existing Markdown documentation provided incorrect CLI syntax, which could lead to confusion and improper execution of slow tests. By updating the documentation to correctly place the -- separator before test tags, Dusan ensured that contributors and users could reliably execute tagged tests as intended. His work demonstrated attention to CLI semantics, open-source collaboration, and documentation best practices, resulting in clearer onboarding materials and more predictable test workflows for the zio/zio community.