We’ll begin by offering the source code (with source file comments included) for the .NET Base Class Libraries (System, System.IO, System.Collections, System.Configuration, System.Threading, System.Net, System.Security, System.Runtime, System.Text, etc), ASP.NET (System.Web), Windows Forms (System.Windows.Forms), ADO.NET (System.Data), XML (System.Xml), and WPF (System.Windows). We’ll then be adding more libraries in the months ahead (including WCF, Workflow, and LINQ). The source code will be released under the Microsoft Reference License (MS-RL).
VS 2008 will include support to automatically retrieve the appropriate .NET Framework source files on demand from Microsoft.
The entire UI library for Forms and WPF. Sounds like this will inlcude all the custom .NET forms controls, including toolbars and the like. Friggin’ cool!