package.el and emacs-version dependencies

[Artur Malabarba]

Is there any code in package.el to prevent the listing of completely
incompatible packages?

If not, would this be a desirable feature, or do we prefer to always
display everything?

Context:
I noticed that, on Emacs 24.3, package.el will list packages that
depend on emacs-24.4, even though they are completely uninstallable.

I realise package.el has changed a lot since 24.3, but I didn't find a
straightforward way to check if this has changed, given that there are
no packages that depend on version > 24.4 (thus my question).