Jatzen enhanced the developer and user experience for Bundler group configuration in both the ruby/ruby and rubygems/rubygems repositories. Focusing on documentation, Jatzen clarified that the 'with' and 'without' options accept both space-separated and colon-separated lists, addressing a common source of confusion for users managing gem installation and exclusion. This work, implemented using Ruby and leveraging expertise in Bundler and technical writing, aimed to streamline onboarding and reduce support queries by making configuration behavior more predictable. While no runtime bugs were addressed, the depth of documentation improvements contributed to smoother workflows and better alignment across core Ruby tooling.