GNOME Screen Sharing VNC 23.04
I previously had 20.04 and then 22.04, and now 23.04. In 20.04, GNOME Screen Sharing offered only VNC. In 22.04, it offered both RDP and VNC. Now in 23.04, it seems to offer only RDP. How can I re-enable the VNC option? (If it makes a difference, I’m logged in using X11, not Wayland.)
Ubuntu 20.04 used the deprecated and unmaintained vino (VNC only) server.
Starting with Ubuntu 22.04, Ubuntu uses gnome-remote-desktop as remote desktop server, instead of vino.
gnome-remote-desktop itself has two backends: One RDP backend, and one VNC backend.
Both backends are build options: While in Ubuntu 22.04, the Ubuntu Desktop Team decided to build gnome-remote-desktop with both backends, they changed that decision to build gnome-remote-desktop only with the RDP backend starting with Ubuntu 22.10.
Thus, there is no more a VNC backend in Ubuntu by default. It is still in gnome-remote-desktop itself, but not in Ubuntus build with 22.10 and later.
The decision was first done by Jeremy Bicha in https://gitlab.gnome.org/GNOME/gnome-remote-desktop/-/commit/55ce55afa1ddb502d4c8e13ae813f348d5f76402 upstream to only build the RDP backend by default.
However, that commit only disables the VNC backend by default upstream, but it can still be enabled when building gnome-remote-desktop.
Then that decision was included in Ubuntu too in https://bugs.launchpad.net/ubuntu/+source/gnome-remote-desktop/+bug/1987159.