Guillermo contributed to the IntersectMBO/hf-wg-documentation repository by updating the Plomin readiness page to reflect new DApp integrations, specifically adding Book.io and Stuff.io to the documented list. He focused on maintaining accurate and up-to-date upgrade readiness documentation, ensuring that stakeholders could easily track integration status during the Plomin upgrade process. Guillermo used Markdown to structure and present the information, emphasizing disciplined documentation practices and clear change traceability through detailed commit messages. While the scope of work was limited to a single feature over one month, the update improved onboarding readiness and maintained synchronization between documentation and ongoing development efforts.