Microsoft has transitioned the development of WinUI and the Windows App SDK to GitHub, marking a commitment to enhance Windows developer technologies. This shift is part of a strategy unveiled in August 2025 to address developer concerns regarding these tools. Mainline WinUI development is now conducted on GitHub, allowing for real-time project evolution and community engagement. Although the technologies have not yet been open-sourced, Microsoft is working towards that goal. Currently, only Microsoft employees can modify the codebase, but there are plans to open the repository for community contributions in the future. This approach follows Microsoft's previous efforts to open source legacy Windows developer frameworks.