Worked on the biomejs/biome repository, focusing on enhancing the stability and data integrity of the migration subsystem. Addressed a critical issue in the strict-JSON migration process, where a renamed rule positioned last in its group could result in an invalid trailing comma, causing migration failures. Applied expertise in Rust and backend development to implement a robust fix that ensures strict-JSON configurations migrate successfully without syntax errors. This targeted solution improved the reliability of configuration upgrades and reduced related customer support incidents. The work demonstrated careful attention to detail in JSON handling and contributed to a more resilient migration pipeline.