Firefox should be able to display the websites' accounts where a user is signed in or out in a device with the possibility to sign in or out with Firefox account.
We can sign in with Firefox account for all websites' accounts as they need only the identity and the password if Firefox can grant access with a code between the website and Firefox to hide the personal data like to confirm identity of a sent messen...
If I can also pay with Firefox account not only to sign in, then I will be a Firefox member proud to be. Yet, we may need also to create an email account like AT firefox.com to book my ticket for the Moon as wealthy as the first man who will land on ...