Only available to users in the owner's account
In the "Edit By Anyone - Publish Links" page, one of the options is "Only available to users in the owner's account."
I have been trying to find documentation as far as what that means exactly, but I don't see any. What does it mean to be "in the owner's account?"
Second question: Ideally, I would want to require people to login, so that I can track who made what change, but I don't really need to restrict anyone from seeing the sheet. Is there a way to do that?