Need help with how Django does URL reversing

[https://docs.djangoproject.com/en/2.2/topics/http/urls/#reversing-namespaced-urls](https://docs.djangoproject.com/en/2.2/topics/http/urls/#reversing-namespaced-urls)

With the docs that I have linked, *step 1* seems pretty clear cut.

Take the example of `'polls:index'`:

* *First, Django looks for a matching* [*application namespace*](https://docs.djangoproject.com/en/2.2/topics/http/urls/#term-application-namespace) *(in this example, 'polls'). This will yield a list of instances of that application.*

After that I'm unclear on *step 2*. What exactly would be a current application if there is a list of application instances as stated in *step1*?

* *If there is a current application defined*, Django finds and returns the URL resolver for that instance.

/r/djangolearning
https://redd.it/cftt7l