Worked on enhancing sitemap handling in the withastro/astro repository by introducing a configurable filenameBase option to the @astrojs/sitemap integration, allowing for custom sitemap file naming and reducing deployment conflicts on specific paths. Updated the configuration schema, adjusted default values, and implemented new file writing logic, ensuring robust test coverage throughout. Complemented these changes with comprehensive documentation and usage examples in withastro/docs, guiding developers on integrating Astro sites into existing domains. Leveraged skills in TypeScript, JavaScript, and configuration management to improve deployment flexibility, maintainability, and developer experience, focusing on feature delivery and documentation rather than explicit bug fixes.