It might be some pattern which prevents this to reach the global context (not in this case, since every variable is declared var, but the author might wanted to use it as a general pattern to create objects).
var x = new (function () {
this.foo = "bar";
return {
// whatever
};
})();
console.log(foo); // Uncaught ReferenceError: foo is not defined
var x = (function () { // without new
this.foo = "bar";
return {
// whatever
};
})();
console.log(foo); // "bar"
