Safari is interesting. It's been separate, except for major macOS updates, which had it bundled. But if you had a newer Safari on an older macOS, and upgraded macOS to anything else that the latest version, then your Safari was downgraded, often causing data loss..

In Sonoma or Sequoia they started bundling all Safari updates with macOS, but right now Safari 26 appeared as a separate update in Sonoma/Sequoia—-and it will likely stay that way.

Each thing separately can be explained, but when put together it’s somewhat messy..