Ah ha, so it's `window`.

The trouble is, the "main" for someone's app. If they are using/requiring many modules, it's like AMD's interface, which is horrible for humans.

```js
YUI().require(['fancy-app'], function (FancyApp) {
  var app = new FancyApp();
  // . . .
});
```

If all I have is the above, where the `fancy-app` module is written as an ES6 module compiled to YUI, that's fine. But if I have many imports, it becomes unwieldily to manage as separate arguments to my callback.

I almost wonder what it would be like if `require()` only accepted one import… and it's intended use would be with a "main" module and helped you bootstrap your app's initialization.