Did Apple inform 'us' of this change or did it just happen along the way ?
Think it just happened. But then it is quite a minor feature really, because it only downloads them, doesn't automatically install them which would be a more major thing.
Where did you find that term ?
A daemon in a computing sense is a background process. Traditionally the processes end with the letter d to reflect this (e.g. sshd).
They do a variety of useful things on a Mac, e.g. whenever you print stuff, cupsd takes care of that (point your web browser to
localhost:631 .... cupsd will say hello ! ), launchd takes care of startup processes etc. etc.
Therefore my guess is that an empdaemon is something along those lines ? But let us know the context of the question as it's not immediately clear.