What are WinRT language projections?

Question

What are WinRT language projections and what are they used for?

Answer 1

The easiest way to clarify is that a language projection in WinRT is the "front end" whereas the Windows Runtime is the backend. Write from one of the three languages (JS, C#, VB), it behaves identically on the back end.

If you write your own 3rd Party WinRT component in C++ or C#, you can use it from JS, C# and VB without having to do any extra work.