Heiko Klein contributed targeted engineering work to the metno/pyaerocom repository, focusing on stabilizing configuration management and improving data integrity. He addressed configuration duplication by refining how model-specific plot type settings are copied and cleaned up across model versions, centralizing version-aware logic in Python to enhance maintainability. In subsequent work, Heiko improved ungridded data handling by fixing data appending logic and refining altitude management for moving stations, reducing the risk of data loss in downstream analysis. His efforts, grounded in Python development and data handling, delivered deeper reliability and consistency to the repository’s processing workflows, despite a short engagement period.