Heh, that is kinda interesting and I've never heard of it before. What are some services that have this set up?

So, I guess you set up some "emergency users". And maybe if you lose access to your account, you get customer support to mark your account as lost which sends an email to the address that you have on file (in case it's an attack started by someone other than the user).

And I suppose if N days pass without any login, one of your emergency users can generate a credential that they can pass to you to recover your account?

Apple accounts have had it for years. You can set up a legal successor if you die, and a couple of people who can vouch for you to regain access.

That and Apple will give you a very long one-time password meant to be printed that can restore access as well. This one is in a third undisclosed location for me.