Accidentally Closing the App - Prevention
I used to work in Android development for years as a product owner, and I know there are pluses and minuses for the feature I'm about to describe, but it's sometimes very handy for people new to the app who don't know how to navigate.
When you use Android's back button to get back to the page you were just at, navigation works as expected. But if you don't pay attention or are new to navigating around the app, it's easy to hit the Android back button too many times and the app closes. Since the app takes a while to re-launch, it's pretty annoying. I've done it several times myself.
So... the feature is simply to put up a prompt asking the user if they really want to close the app when they hit the back button from the base navigation page.