Question regarding federation of user data.

So, I understand that all interactions we make like posts and comments are visible from anyone.

Even though I believe it's a bit less private than I'd like I also believe that upvotes and downvotes are federated, I wonder if they're federated in a more private way using some hash or something or if it's just openly federated.

What about the email I had to use to register here? Hopefully this one lives only with the database of the this instance and it's not federated at all.

Cheers