Mariana Garces enhanced build reliability and determinism across the dotnet/msbuild and dotnet/sdk repositories by developing three targeted features in C# and XML. She improved the DownloadFile task in msbuild to derive filenames directly from the DestinationFileName or request URI, eliminating dependency on server response headers and ensuring consistent artifact naming. Mariana also automated versioning updates for Versions.props, synchronizing opt-prof runs across multiple release branches for reproducibility. Additionally, she upgraded the build system in dotnet/sdk to MSBuild 17.14.5, updating NuGet configurations and version properties to align with current SDK requirements. Her work emphasized robust build management and automation.