The piece which requires state is the 'user consented to sharing data X with app Y' bit so that the user can change that consent in the future.
The email relay address could feasibly be just a reference to that state.
The email relay address could feasibly be just a reference to that state.
They've also explicitly stated that they will not record any information about interaction with a service.
Based on Apple's general approach to data security, I suspect that there is no "company A got alias address Y" table. In principle all that they need is a table of alias->real. On the other hand maybe it would be useful to have such a table in the case a site gets compromised/starts selling information?
But they have stated explicitly in a public video that they will not record interactions or emails you send, so I'm sure it would be lawsuit city if the reneged on that.