Firebase Authentication: Where is the token stored in web?

I was curious about how firebase auth token works.
Then I found this answer saying that token is stored in local storage.
https://stackoverflow.com/a/62577638/7239472

However, when I checked local storage in Application tab of my Google Chrome inspector, there was nothing.

So from where does the Firebase Auth SDK get the token value?

I also checked that currentUser object contains token value but I'm not sure where that came from.