I'm using Alien Bob's KDE 5 package and I kept getting that infamous bug where it would start into a black screen where all you had was a mouse cursor.
After
much debugging, I managed to figure out what the problem was.
I'd had the LS_COLORS file from
https://github.com/trapd00r/LS_COLORS as my ~/.dir_colors, and
that, amazingly enough, was what was causing KDE to break.
Have I reported this to the KDE devs? I should, but no I haven't.
Anyway, just thought the KDE 5 users here would like to know.