I think the post is very explicit. First sentence:

> Starting later this year, new Sign in with Apple addresses, previously issued on privaterelay.appleid.com, will be issued on private.icloud.com. Existing addresses on privaterelay.appleid.com will continue to work and forward mail to users without interruption.

How many sign ups you have with an @icloud.com address?

A lot of those are Hide My Email aliases that, by design, you can’t tell apart from real human addresses.