Tony van Swet worked on the electricitymaps-contrib repository, focusing on improving the reliability of time-based chart visualizations. He addressed a bug where the midnight marker was not visible or properly aligned on mobile devices by adjusting its vertical positioning and ensuring the marker line extended correctly across varying chart heights. Using React and TypeScript, Tony’s changes enhanced chart readability and reduced user confusion, particularly on responsive layouts. He also reverted an incorrect branch change to maintain rendering stability. His disciplined approach to change management and clear commit history demonstrated attention to detail and readiness for quality assurance and release processes.