Questions:Setting up policykit-1 (0.105-18+deb9u1) ...
Setting up raspberrypi-ui-mods (1.20181206) ...
The desktop has been updated.
To apply the updates, please reboot your Pi, and then select one of the options on the Defaults page in Appearance Settings.
No protocol specified
Unable to init server: Could not connect: Connection refused
(zenity:5110): Gtk-WARNING **: cannot open display: :0.0
Processing triggers for libc-bin (2.24-11+deb9u3) ...
1) What's up with the stuff about a "Defaults page in Appearance Settings"? How/where is there a "page" in terms of configuring the desktop?
2) Why the zenity errors?
Note regarding #2 above: I was running on the desktop, logged in as "pi", but "sudo'd" to root. I suppose the error happens because some process running as root doesn't have access to the X session. Can this be fixed?