> I see. It looks like `apt upgrade <package>' behaves as `apt install
> <package>'. Which (to me) is unexpected behaviour, as the man page is quite
>clear on its behaviour (man 8 apt-get):
Well, clearly it shouldn’t. To begin with, “apt install” should mark a package as manual installed while “apt upgrade” shouldn’t (my assumption). And you’re right that “apt install” can remove a package if needed to satisfy dependencies.
On top of that, documentation clearly states that “apt upgrade” should not remove any package, but it does when you specify an individual package to upgrade.
If this is not the expected behavior, maybe this is a bug (unless I am missing something here).