Download the entire source code of .NET Framework 4.6.1 as a .zip file. The archive includes a solution and project files that can be opened in Visual Studio. This solution will not build because it is missing crucial components such as resources, XAML files, etc. but it will be sufficient to browse the source code inside Visual Studio.

.NET 4.6.1 for Windows 10 November Update (59 MB) .NET 4.6.1 for Windows 7 SP1, Windows 8, Windows 8.1, Windows 10, Windows Server 2008 R2 SP1, Windows Server 2012, and Windows Server 2012 R2. (59 MB)