firebase-tools is a popular library built by Google providing abstractions to develop and deploy Firebase applications. firebase-tools is the recommended way for deploying serverless functions to Firebase / Google Cloud. Firebase is a service built on top of Google’s cloud platform.
The Firebase Command Line Interface (CLI) Tools can be used to test, manage, and deploy your Firebase project from the command line.
Deploy code and assets to your Firebase projects
Run a local web server for your Firebase Hosting site
Interact with data in your Firebase database
Import/Export users into/from Firebase AuthSource: firebase-tools — npm (npmjs.com)
I have used Firebase for about two years to develop a web application. A while back, I also started using native Google Cloud features like Secret Manager to store secrets directly in the cloud. And precisely, the usage of Secret Manager should reveal a fatal flaw in the standard setup of firebase-tools and, more specifically, how Firebase recommends authenticating on personal and CI/CD environments.