Comment 7 for bug 1803504

OK, before working on your to do list .....

Yesterday with an update (Start-Date:2018-11-15 13:49:41) on this linux box there where ...libegl-mesa0... in the list of modules.
There where no indication of restart required but I reboot the system .... and the graphic was frozen.
See picture attached.
There was no possibility to use the mouse or the keyboard to get out of this state.

But with ssh I can connect in.

You will find also the file var_log_apt_history.log where you find the re-installation of the ubuntu-gnome-desktop (Start-Date: 2018-11-14 11:49:00) which results in recover the screen graphic.