Is this behavior now part of Django?

[frnhr]

I cannot find any reference to it (probably haven't looked hard enough), but in practice it looks like Django automatically finds the "overextended" template by default. At least on 1.10. I am sure that a few years ago it was not the case, I needed django-overexdends for that.

Are there any cases where this app still provides a benefit?

[stephenmcd]

No idea.