Marco contributed to the PrismLauncher/PrismLauncher repository by addressing a critical bug affecting the import of modpacks from newer FTB App instances. He enhanced the reliability of the import process by updating the parser logic to prioritize .ftbapp/version.json over the legacy version.json, ensuring accurate detection of updated file structures. This change reduced import failures and streamlined support for evolving modpack ecosystems. Marco’s work demonstrated proficiency in C++ and robust file handling, with careful attention to maintainable and traceable code. The solution focused on JSON parsing and modpack management, reflecting a targeted, in-depth approach to improving user experience and codebase reliability.