I've used rsync again for this because I found it very simple, I've only excluded the Cache directory since it's not necessary and could be several GB in size.
rsync -Phaz --exclude=Cache/* firstname.lastname@example.org:/home/user/.mozilla/firefox/profile.default/* /home/user/.mozilla/firefox/ec1n9opl.default/
This is a great way once again to get going how you were on the old/remote computer fairly quickly. It even restores all of your history including the very tabs that were open and also includes your bookmarks, settings and addons too!
howto, restore, firefox, settings, preferences, addons, bookmarks, desktop, ve, rsync, excluded, cache, directory, gb, phaz, exclude, user, remotehost, mozilla, default, ec, opl, restores, tabs, includes,