If you decide to apply infamous advice and move fast and break things, then you should be prepared to fall back to a working version. Luckily Firebase Hosting allows rollback quickly, but there's one problem: it's hard to determine which version you need. To solve this problem, you can mark deployments with current git tag or link to commit at GitHub:
firebase deploy \ --message "https://github.com/username/repo/commit/$(git rev-parse HEAD)"
Then when you move too fast and finally break things, you can easily find the version you need: