How to enable guest sessions on Ubuntu 18.04 or later?
Solution 1:
Is there any way you could revive Guest Sessions in a future LTS distro?
You seem to believe we can get this back into a distribution but we are just users (except for a couple of people that are also employees of Canonical).
And if you want it back: install LightDM.
sudo apt install lightdm
Create a configuration file
sudo gedit /etc/lightdm/lightdm.conf.d/50-enable-guest.conf
and copy the contents below to it:
[Seat:*]
allow-guest=true
Reboot the computer and pick lightdm at the login screen.
Do read the wiki page CustomizeGuestSession and the discussion on removing guest accounts.
Before you start using it: Guest Account is NOT secure: the data from normal users on the system is not secure from the guest. The same goes for the data from the guest. And the guest can view system files.