January 2025 monthly summary for open-energy-transition/pypsa-earth: Delivered configuration cleanup and standardization that reduce conflicts, improve maintainability, and enable smoother future enhancements. Key outcomes include removal of duplicated hydrogen_underground_storage: true entries across default and test configurations to prevent conflicts, and standardization of gadm_level into a single gadm_layer_id parameter across scripts and build_shape_options to reduce configuration redundancy and confusion. These changes enhance reliability, onboarding, and cross-environment consistency, setting the stage for faster feature delivery and fewer misconfigurations. Technologies demonstrated include Python, configuration management, and targeted refactoring focused on code hygiene. Commit references illustrate precise changes: for the bug fix, 'remove duplicated config entry' and 'remove duplicated entry in config.test_myopic'; for the feature, 'remove duplicated gadm_level'.