It might have changed in the newer releases of Ubuntu, but on 16.04 (Unity desktop) `dbus-user-session` is NOT installed by default and NOT a dependency of any standard packages.
I myself got it as dependency of Anbox. Now that this is gone, the only remaining thing that points to this package is `dbus`, but as a suggestion. Suggestions are optional dependencies that do not automatically get installed unless you explicitly command `apt` to do so.
Also if you would remove something which another (meta-)package recommends or suggests (not hard dependencies), that wouldn't uninstall this other package. And even if so, in case of the desktop meta-packages like `ubuntu-desktop` it would not make a difference anyway, as these don't have a function other than initially installing all stuff. No harm in them being removed.
It might have changed in the newer releases of Ubuntu, but on 16.04 (Unity desktop) `dbus-user-session` is NOT installed by default and NOT a dependency of any standard packages.
I myself got it as dependency of Anbox. Now that this is gone, the only remaining thing that points to this package is `dbus`, but as a suggestion. Suggestions are optional dependencies that do not automatically get installed unless you explicitly command `apt` to do so.
Also if you would remove something which another (meta-)package recommends or suggests (not hard dependencies), that wouldn't uninstall this other package. And even if so, in case of the desktop meta-packages like `ubuntu-desktop` it would not make a difference anyway, as these don't have a function other than initially installing all stuff. No harm in them being removed.