xorg-server -listen unix option doesn't create a UNIX socket in /tmp/.X11-unix

[rustyx]

The X server in Kubuntu 24.04 no longer creates UNIX display sockets in /tmp/.X11-unix, even after enabling both abstract sockets (-listen local) and UNIX sockets (-listen unix):

$ pgrep -a Xorg
1991 /usr/lib/xorg/Xorg -listen local -listen unix -listen tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_SfFvKB -noreset -displayfd 16
$

$ ll /tmp/.X11-unix/
total 2256
drwxrwxrwt 2 root root 4096 nov 26 2024 ./
drwxrwxrwt 22 root root 2301952 nov 26 2024 ../
$

I expected that the -listen unix option would create UNIX sockets. Without UNIX sockets many apps fail to connect to the X server (e.g. docker, ssh).