Download the entire source code of .NET Framework 4.7.2 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 4.7.2 for Windows 10 April 2018 Creators Update (63 MB) .NET 4.7.2 for for Windows 7 SP1, Windows 8.1, Windows 10 Anniversary Update, Windows 10 Creators Update, Windows 10 Fall Creators Update, Windows Server 2008 R2 SP1, Windows Server 2012, and Windows Server 2012 R2 and Windows Server 2016e (63 MB) .NET 4.7.2 ZDP Update (63 MB)