I think you will find Firefox is NOT part of the Update Packs because it comes from the Linuxmint Packages repos not Debian Testing copies used for update packs. So, there may be a trickle of updates in those repos but nothing in "Packs".
Not before time that Firefox has had an update as well. Getting a bit embarrassing for the so-called new "wonder kid" of Linux to be languishing at v5 of Firefox?!
Clem made it quite clear (in his closing the 'Sleeping Distro' thread) that LMDE-Xfce users can "take a hike" regards updates until he is good & ready - even though the Gnome3 issues have little or no bearing on them AT ALL!
I am currently migrating over 100 users off LMDE-Xfce ( as there is no interest in supporting that distro here whatsoever). Last night, did another fresh install of Debian Testing weekly build with Xfce DE, added all relevant codecs, drivers etc and a handful of updates to be up & running (themed according to preferences) within about one & a half hours, start to finish. It would take longer than that just to download the upgrade packages to shift LMDE to Testing!! (Clem's suggestion)
Good luck with the waiting.
rhodry.
Life isn't about waiting for the storm to pass...
it's about learning to dance in the rain.