Bundling and minification techniques were introduced in MVC 4 to improve request load time. Bundling allow us to load the bunch of static files from the server into one http request.
MVC 5 includes following bundle classes in System.web.Optimization namespace:
StyleBundle: StyleBundle is responsible for CSS minification of single or multiple style sheet files.
DynamicFolderBundle: Represents a Bundle object that ASP.NET creates from a folder that contains files of the same type.
All the above bundle classes are included in System.Web.Optimization.Bundle namespace and derived from Bundle class.