MVC5 Store and manager classes

I know the MVC pattern which stands for Model View Controller. But Where do Store and Manager class files come from?

I started My project with MongoDB and i implemented the MongoDB.AspNet.Identity. Which is an extension of the Microsoft.AspNet.Indentity with the EF.

But when looking at the AccountController that is provided by this package they are using the following code.

        public AccountController()
        : this(new UserManager<ApplicationUser>(new UserStore<ApplicationUser>("DefaultConnection")))
    {
    }

Now my questions:

1. What is the prupose of the Manager class
2. What is the purpose of the Store class?
3. And why is the UserManager passed to the Controller of MVC?
4. And to what pattern belong the Manager and Store classes?