Where is player data saved, if a project is not linked to Unity Services?

I am trying to understand how Unity Services work. I downloaded the sample project and run the “Idle Clicker” game, and it worked fine - when I stopped the game and restarted it, my balance was retained and even increased (as expected from an Idle Clicker game).

But then I wondered where the information is saved. It is probably saved in the Unity Cloud, but under what account? I looked at Edit → Project Settings → Services, and saw that the project is not linked to any Unity Cloud account (screenshot)

Similarly, under the Authentication service I saw the same screen I see when the project is not linked to the cloud (screenshot).

I then linked the project to my Unity ID and ran it again, but this time I got an error (screenshot).

Now I do not understand what is going on: (1) Where was the information saved when the project was not linked? (2) Why did it stop working when I linked it to my Unity cloud account?

Hi!
Sorry for delay, just returning from the holidays.

You can paste screenshots directly here:

I havent got access to any of the screenshots you linked unfortunately.

To answer your questions,

(0) But then I wondered where the information is saved.

Yes, it is stored in the cloud-save service

(1). The project as-is is already linked to a project maintained by us. It will work on play, since its already configured properly, but you cant see the details because you dont have a developer role on that project, so it appears unlinked because you’re not a developper. To finish the local setup, you have to follow the readme, including, as you guessed, creating and linking your own project.

(2) This part I have to assume some stuff, since I cant see your screenshot. Linking your fresh project doesn’t mean its configured. Check the readme, it requires you to deploy the cookie-clicker configuration.

Let me know if you need any more help