为什么VS 2013将ASP.NET MVC 4 web.config复制到bin并重命名？

I just noticed that during a build, Visual Studio 2013 is copying the web.config from the root of my ASP.NET MVC 4 web app project into the bin folder and renaming it for the resulting web app DLL with a .config extension. It's a straight copy because the files have the same timestamp.I just noticed that during a build, Visual Stud