I haven't had need to mess with X for a long time (I'd guess it was still when Xfree86 ruled). A few weeks ago, however, I was trying to get a laptop to use an external display and I managed to cripple the setup (annoying flashing screen).
Since the laptop was already due an upgrade (and I had a backup of
/home) I just upgraded to F24 and moved on, but it got me thinking that I should probably have a backup of a working configuration.
What files should I backup in case I need to mess with X again?
Or should I just backup everything in
/etc and not worry about specifics?