This repository demonstrates using the firebase/auth functionality.
The endpoint /desktopSignIn redirects the user to google authentication.
Once authenticated the user returns to the web app. The web app then makes use of the function in electron-firebase-auth-functions to retrieve a custom token.
The web app then redirects the user to the custom protocol my-app://signIn?authToken=XXX, which is assumed to be handled by an installed application.
This flow is suitable for custom authentication within an untrusted application.