There are security features that Apple tells us about on stage at keynotes, and then there are hidden improvements it doesn’t mention.
macOS has gradually made the UNIX security model irrelevant. For example, even the superuser is only allowed to access the private documents of a regular user with the user’s permission—permission that is given on a per-application basis, through that protector of users and bane of developers known as the Transparency, Consent & Control (TCC) framework.
Check It Out: The Secret Security Features in macOS Big Sur