That's for Debian. In most cases, FreeBSD has a similar setup, though the naming can be confusing, RELEASE, STABLE, and CURRENT. (See Fred Cash's explanation at
http://srobb.net/release.html).
I don't have answers for you. I don't know how strongly it's connected to what is considered a FreeBSD strength, that the base system and userland are separate. The Linux distributions that don't separate these things might have caught this or fixed it earlier, I have no idea.
I agree that these are two frequently used ports, (NVidia even more than VirtualBox, as a lot of people are switching to bhyve) and the problem of the modules causing kernel panics are bad, especially since VirtualBox is often used with Vagrant, a program used more on servers. In my own, relatively meaningless, personal opinion, for desktop users, these two should have been given more attention in the release announcement, since, though in theory, everyone should read all the erata, I suspect many just skim through it. A big, UPGRADING TO 11.2 MAY BREAK VIRTUALBOX AND NVIDIA a
in ALL CAPS
might be a good idea. An announcement on these forums would also be useful, even if they are an unofficial channel, especially as I'm sure it got mentioned on distrowatch and lots of folks with little experience may try it.
And for you naysayers who don't care about that crowd, ya never know. One of them might be the one to get synaptic working out of the box and 802.11ac wireless speeds. And for those of you who don't care about that because you only use servers, I don't care about you either, because I use laptops and am incredibly selfish, especially since some nasty illnesses.
I care about servers and laptops too.
http://srobb.net/selfish.mp4