During September 2021, Jmlntw focused on improving dependency management reliability by addressing lockfile formatting inconsistencies in the rubygems/rubygems and ruby/ruby repositories. They resolved two bugs by standardizing lockfile spacing to single spaces, enhancing both readability and cross-repository consistency. Working primarily with Ruby and Ruby on Rails, Jmlntw updated related tests to ensure the new formatting was enforced and to provide regression coverage against future spacing issues. Their work demonstrated a methodical approach to software development and testing, emphasizing maintainability and clarity in version control practices, though the scope was limited to targeted bug fixes rather than new feature development.