How to disable autostarting x11vnc session?

I've had a Ubuntu system running for ages. It was originally installed as a mythbuntu variant. I don't remember which version it started at but I've recently upgraded to 18.04.

Since it is connected to a tv in the living room it's very convenient to have a vnc session to do remote maintenance and config. Many moons ago I configured x11vnc to start with the main display (:0) using a forgotten howto page and it's worked well for ages.

After the 18.04 upgrade, and possibly some other system changes (sideeye IBM & Oracle Java runtime installs) I can still connect to the desktop over vnc, but if I click on the 'Applications' menu the vnc server exits and I can't reconnect until I reboot. I'm able to work with terminal windows that are already open with no problem.

I don't know where to start with debugging the vnc crash. I thought it would be easier to try a different vnc server like TigerVNC.

Unfortunately I tripped on the first step down that path, which was to stop x11vnc from starting automatically.

I've googled a wide range of the howto pages that I might have used back then to set it up, thinking I'd just undo things, but I can't find any of the config files those pages reference. I've been going around in circles for a while.

**At this point I'm hoping for a new hint that will start me down a productive path. A config filename, anything. **

I'll paste in some console output below that (in my imagination) might be helpful.

Thanks, Andrew

Edit: I've taken the nuclear option and removed the x11vnc package. Next step will be figuring out how to replace it...

acodring@mythbackend:/var/log$ sudo apt-get autoremove x11vnc
<snipped>
The following packages will be REMOVED: libegl1-mesa libvncclient1 libvncserver1 netcat-traditional x11vnc x11vnc-data
<snipped>
acodring@mythbackend:/var/log$ sudo reboot
Connection to mythbackend closed.

Last login: Wed May 27 15:19:55 2020 from ...
acodring@mythbackend:~$ ps aux | grep vnc
acodring 2910 0.0 0.0 14352 1004 pts/5 S+ 16:10 0:00 grep --color=auto vnc
acodring@mythbackend:~$

Original details:

acodring@mythbackend:/etc/X11$ uname -a
Linux mythbackend 5.3.0-53-generic #47~18.04.1-Ubuntu SMP Thu May 7 13:10:50 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

acodring@mythbackend:/etc/X11$ x11vnc --version
x11vnc: 0.9.13 lastmod: 2011-08-10

acodring@mythbackend:/etc/X11$ ps aux | grep vnc
acodring 535 0.0 0.0 14352 1008 pts/5 S+ 18:02 0:00 grep --color=auto vnc
acodring 1466 0.6 0.9 188396 76744 ? Ss May24 21:26 x11vnc -rfbauth /home/acodring/.vnc/passwd -rfbport 5900 -shared -forever -nowf -norc -notruecolor -bg -xkb

acodring@mythbackend:/etc/X11$ sudo locate x11vnc.conf
acodring@mythbackend:/etc/X11$ sudo locate x11vnc.service
acodring@mythbackend:/etc/X11$ sudo locate x11vnc
/usr/bin/x11vnc
/usr/share/x11vnc
/usr/share/app-install/desktop/x11vnc:x11vnc.desktop
/usr/share/applications/x11vnc.desktop
/usr/share/doc/x11vnc
/usr/share/doc/x11vnc-data
/usr/share/doc/x11vnc/README.gz
/usr/share/doc/x11vnc/changelog.Debian.gz
/usr/share/doc/x11vnc/copyright
/usr/share/doc/x11vnc-data/changelog.Debian.gz
/usr/share/doc/x11vnc-data/copyright
/usr/share/man/man1/x11vnc.1.gz
/usr/share/x11vnc/classes
/usr/share/x11vnc/classes/VncViewer.jar
/usr/share/x11vnc/classes/index.vnc
/usr/share/x11vnc/classes/ssl
/usr/share/x11vnc/classes/ssl/README
/usr/share/x11vnc/classes/ssl/SignedUltraViewerSSL.jar
/usr/share/x11vnc/classes/ssl/SignedVncViewer.jar
/usr/share/x11vnc/classes/ssl/UltraViewerSSL.jar
/usr/share/x11vnc/classes/ssl/VncViewer.jar
/usr/share/x11vnc/classes/ssl/index.vnc
/usr/share/x11vnc/classes/ssl/proxy.vnc
/usr/share/x11vnc/classes/ssl/ss_vncviewer
/usr/share/x11vnc/classes/ssl/ultra.vnc
/usr/share/x11vnc/classes/ssl/ultrasigned.vnc
/var/lib/app-info/icons/ubuntu-bionic-universe/64x64/x11vnc_computer.png
/var/lib/app-info/icons/ubuntu-xenial-universe/64x64/x11vnc_computer.png
/var/lib/dpkg/info/x11vnc-data.list
/var/lib/dpkg/info/x11vnc-data.md5sums
/var/lib/dpkg/info/x11vnc.list
/var/lib/dpkg/info/x11vnc.md5sums
acodring@mythbackend:/etc/X11$

acodring@mythbackend:/etc/X11$ sudo locate X*.d
/etc/X11/Xreset.d
/etc/X11/Xsession.d
/etc/X11/Xreset.d/README
/etc/X11/Xsession.d/20dbus_xdg-runtime
/etc/X11/Xsession.d/20x11-common_process-args
/etc/X11/Xsession.d/30x11-common_xresources
/etc/X11/Xsession.d/35x11-common_xhost-local
/etc/X11/Xsession.d/40x11-common_xsessionrc
/etc/X11/Xsession.d/50x11-common_determine-startup
/etc/X11/Xsession.d/55xfce4-session
/etc/X11/Xsession.d/60x11-common_localhost
/etc/X11/Xsession.d/60x11-common_xdg_path
/etc/X11/Xsession.d/70gconfd_path-on-session
/etc/X11/Xsession.d/75dbus_dbus-launch
/etc/X11/Xsession.d/90consolekit
/etc/X11/Xsession.d/90gpg-agent
/etc/X11/Xsession.d/90qt-a11y
/etc/X11/Xsession.d/90x11-common_ssh-agent
/etc/X11/Xsession.d/95dbus_update-activation-env
/etc/X11/Xsession.d/99x11-common_start

acodring@mythbackend:/etc/X11$ sudo update-alternatives --display java
[sudo] password for acodring:
java - manual mode link best version is /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java link currently points to /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java link java is /usr/bin/java slave java.1.gz is /usr/share/man/man1/java.1.gz
/opt/jre/jre1.8.0_251/bin/java - priority 100
/usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java - priority 1081 slave java.1.gz: /usr/lib/jvm/java-8-openjdk-amd64/jre/man/man1/java.1.gz
/usr/lib/jvm/java-ibm-x86_64-80/jre/bin/java - priority 80

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