Docs
How it decides what has an update, what it checks before replacing an app, and what macOS will ask you for.
How it worksWhere each version number comes from, and why the install route differs per app.Install safetyWhat is checked before an app is replaced, and what is deliberately never done.PermissionsWhat macOS will ask for, what each one buys, and what you lose by declining.PrivacyNo telemetry, no analytics, no server — and the three cases that read outside our own container.The duo commandThe same engine as a command-line tool, and the two things it refuses to half-do.