It's not clear to me if a PlayFab user account is:
a) A global account, across the whole of PlayFab, with the same email address and password across all titles (my titles and those from other publishers).
b) A publisher-specific account, common across all of my titles.
c) A title-specific account within my game across all platforms.
This drastically affects how we need to brand the login/register page so that the user knows what to do (and they know if they need to re-use an existing login or create a new one).
Is this explained anywhere?