This is why Debian users should use apt-listchanges to display the latest NEWS.Debian items on upgrade.

I wouldn't expect to see all the important news of the tens of thousands of packages I don't have installed in the release notes.

I was hit by this using unstable (before they made a NEWS item), but when upgrading my stable machines to trixie I got a proper warning/reminder of this specific thing.

You’re not wrong in general terms, but tzdata is fairly well essential, a default component, and a dependency for unpteen things in the ecosystem. Of course a line must be drawn somewhere, but this really is a “major” caveat.