there is no more plasma!
I don't recall the names/numbers of the update, but there were 62 packages. Since there had also been a new 4.17 kernel in the update just minutes previously and I hadn't rebooted, I did this update, too, and powered off for the night. This morning, using both the new 4.17 kernel and the last of the 4.16 kernels, trying both plasma on xorg and on wayland, I log in and there us just a black display with a mouse pointer.
I had to resort to gnome in order to be able to have a desktop at all.
That happened? Is there some undocumented dependency that did not get pulled into the update that I need to install? I tried doing an update just moments ago, but it says the system is up-to-date.