Appcheck - debug provider instructions unclear.

[PaulRudin]

https://firebase.google.com/docs/app-check/android/debug-provider#emulator

Says "in your debug build" - for flutter developers without experience of writing native apps it's unclear what file(s) should be modified here?

Also - the kotlin code snippet includes FirebaseApp.initializeApp(/*context=*/this), but the firebase app is initialized in flutter code normally? Will this work?

The instructions here: https://firebase.flutter.dev/docs/app-check/usage#activating-the-debug-provider-android
are similar, but talk about modifying MainActivity.java, By default new flutter projects don't have this file do they? In this case the instructions make no mention of "debug builds" - does this mean that the snippet should be included unconditionally in all builds?

A working example app using the debug provider would be a great help.