What does `true` means in firebase database rules

Question

I'm starting with firebase and i've a very basic question

in firebase rules for database i've:

{
  "rules": {
    ".read": true,
    ".write": true
  }
}

According to google it means that anyone can read and write on database.
My question is who anyone?

Let me clarify:

1. I don't want to force the user of my app to login, nor to have an account on google in order to use it.
2. this project is not shared with other people, other apps or any other stuff

is it possible to somebody to access the data stored in firebase? if yes how?

again if yes, what should i do to protect the data without forcing users to have credentials?

Answer 1

Waitting for answers