When I install apps from Apple App Store, I noticed in the App Store’s privacy details that under “Data Linked to You,” there are “User ID” and “Device ID.” I have the following questions:
Device ID
What Device ID will the app obtain? From my findings, in iOS/iPadOS, the “Device ID” can be UUID/IDFA/IDFV, and I have a good understanding of these data types, each of which is not a fixed and unchangeable identifier.
However, on macOS, non-sandboxed apps can easily access unique hardware identifiers such as UDID, device serial number, and hardware MAC address for tracking users. Therefore, I would like to know if sandboxed macOS apps can access these unchangeable identifiers that can be used to track me across different apps.
User ID
Apple’s official documentation defines User ID as: “Such as screen name, handle, account ID, assigned user ID, customer number, or other user- or account-level ID that can be used to identify a particular user or account.” I don’t quite understand this description. Besides the account information within the app, does this information include any data related to my Apple ID? (Assuming I do not use Apple to register for the app.)
Link Method
Since the above two data types are described as “data linked to you,” I would like to ask how they are linked to the user. Is it through Apple ID or iCloud? Does this risk leaking some unchangeable identifier related to my Apple ID?