XDG_SEAT, XDG_VTNR, XDG_SESSION_ID not set

[kenn]

I installed Ubuntu 20.04, it is running well. I switched display manager to lightdm. I noticed that it fails to set environment variables XDG_SEAT, XDG_VTNR, XDG_SESSION_ID.
I also tested gdm3, it's the same. I also tried liveiso to no vail.

apt-cache policy lightdm
lightdm:
  Installed: 1.30.0-0ubuntu3.1
  Candidate: 1.30.0-0ubuntu3.1
  Version table:
 *** 1.30.0-0ubuntu3.1 500
        500 http://archive.ubuntu.com/ubuntu focal/universe amd64 Packages
        100 /var/lib/dpkg/status

[Sebastien Bacher (seb128)]

Thank you for your bug report, why do you expect those to be set? Does it create any visible issue?

[kenn (whatnext)]

Thank you for responding. I wonder if it's intended by design.
I used to logout via
`dbus-send --system --print-reply --dest=org.freedesktop.login1 /org/freedesktop/login1 'org.freedesktop.login1.Manager.TerminateSession' string:$XDG_SESSION_ID`
or
`loginctl kill-session $XDG_SESSION_ID`
in my scripts.

I can live without them.
Did developers drop those environment variables?
Another question:
Is that issue related to `lightdm` or `systemd`?
Regards.

[Launchpad Janitor (janitor)]

[Expired for lightdm (Ubuntu) because there has been no activity for 60 days.]