Piet Hein Koelemij focused on enhancing the myparcelnl/developer repository by delivering comprehensive documentation for the Priority Delivery shipment option. He clarified the availability, usage, and behavior of this feature, updating and reorganizing object definitions to improve API consistency and developer understanding. Using Markdown and applying skills in API design and technical writing, Piet Hein alphabetized related definitions and cleaned mailbox references, which streamlined navigation and improved maintainability. Although no bugs were fixed during this period, his work addressed long-term documentation quality, making onboarding easier for developers and ensuring the repository’s technical references remained clear, organized, and up to date.