Documentation for connecting a Flutter web app to Firebase Emulator UI?

[skillitzimberg]

I put a question to Stack Overflow about this, but I'm either so confused that the question meaningless or I'm the only person struggling with this. (I'm guessing the former is true.)

When I run the emulators (firebase emulators:start), the hosted app is using the production Firestore database and, as far as I can determine from the Emulator UI logs, the deployed cloud functions.

When I use Postman to trigger an emulated http function, it is pointing to the emulated db, so that seems to be working as expected.

How do I set this up so that if the emulators are running the locally hosted app works with the emulated db instead of production?