@timgraham: Hmm, I don't remember anymore. Perhaps I noticed that it wasn't used anywhere and wasn't part of the tests. You're right, though - we'll have to leave it in if it's documented.

It'll be a bit of a slog, but I can add update the [tests](https://github.com/django/django/blob/master/tests/urlpatterns_reverse/tests.py#L653) to check it as well.