Developed a feature for the matplotlib/matplotlib repository that enables customizable arrowhead width and angle for box-style annotations, enhancing the flexibility of data visualization. The implementation introduced new parameters to the relevant arrow classes using Python, with a focus on maintainable code and robust unit testing to ensure reliability. Comprehensive documentation updates accompanied the feature, providing clear usage examples and improving accessibility for users. No major bugs were addressed during this period, allowing concentrated effort on feature depth and test coverage. The work demonstrated proficiency in Python programming, data visualization techniques, and disciplined version-control practices within a collaborative open-source environment.