There are multiple teams working on it.

- Framework team responsible for the Framework itself
- C# team that maintains and enhances C#
- VB team that maintains and enhances VB
- Data Tools that maintains tools for exposing the database is Visual Studio
- ASP.Net responsible for web tools
- Visual Studio shell that handles the common VS stuff
- and others

Each language team is responsible with determining what Framework features they expose and how to expose them, although I can't imagine not exposing framework functionality. They also deal with how Visual Studio works for their particular language and what additional tools they want to create.

There is no one responsible for "referential integrity of .Net".


>Where are the people who are supposed to be enforcing the referential integrity (if you will) of .NET? Did they just sell us a bill of goods and now already it's just every language for itself?