T4: Text Template Transformation Toolkit? An upgraded version of C4?

What is T4? Has it something to do with C4?

Visual Studio.Net has a little known code generation feature called T4 templates since version 2005. It was introduced to facilitate Domain Specific Languages (DSL’s). With it you can make code generation templates like the ones CodeSmith has but without the GUI. A free GUI can be downloaded here.

You can find more information about T4 here and here.