At present, if you hit ctrl-alt-backspace in UB20.10, the X session is terminated and you lose any outstanding state.
Since there is no useful purpose for this, and it carries dataloss risk, this should be disabled. Can anyone chime in what change is needed?
org.gnome.desktop.input-sources
xkb-options
Use dconf-editor to navigate to the path and edit the xkb key
I agree we can work around it, however it’s a game-over scenario if a UB user runs into this and finds they can kill the login session without confirmation like this.
Maybe it’s better to disable this developer feature by default?
Think of it as a soft “get out of jail”. You can do more damage by pressing and holding the power off button than just killing the session.
So if you get a situation that you just can get out of - kill the session. If things still can’t be resolved then power off.
I agree, though the user has the option to enable a single press of the power button to do a clean shutdown, which is a more intuitive path. A developer would kit ctrl-alt-f1, login and replace the window manager or such.
Ctrl-alt-backspace works from the lock screen, so unauthenticated users can arbitrarily and easily kill sessions, which is why it was disabled eg in Ubuntu Gnome, so please consider.
Please leave ctrl-alt-bs in. When the video driver goes down or X locks up, it’s the fastest and easiest way to reset and get back to work.
It’s also the easiest to explain to somebody over the phone.
The keys are pretty far away from each other so the error case where somebody presses all 3 at once is minimal. And if somebody is going around blindly searching for hotkey combos - they get what they deserve. 
Seriously, ctrl-alt-bs is a tool and it’s saved my bacon many times.