TodoMVC is the same to-do application written using numerous frameworks.
The concept here is to help you decide which MV* framework to choose from the vast choice available nowadays.
As of now, the application is written with Backbone, Ember, Spine, Sammy, jQuery, and other popular frameworks.
The source code for each is provided so you can explore and find the right fit for you.
This approach only allows you to become familiar with code syntax and the model/view/controller attitudes in the framework; that’s why the developers encourage you to browse the official documentation and feature list of each framework.