Visual Studio Software Development Kit (SDK)
The Visual Studio SDK includes documentation, samples, and code to help you develop products that integrate with Visual Studio.
To download the latest Visual Studio SDK release, go to the Microsoft Download Center.
In Visual Studio 2013 Update 2, some changes have been made to the Visual Studio project system to manage the new universal Windows app project type. For more information, see Universal Windows Apps. For a walkthrough that demonstrates the changes, see Walkthrough: Managing Universal Windows Projects.
For information about the assemblies that have changed in Visual Studio 2013 Update 2, and the version number you should use to reference them, see Referencing Assemblies Delivered in the Visual Studio 2013 SDK Update 2.
The Visual Studio Extensibility Developer Center on the MSDN website offers the news and information about Visual Studio extensibility.