Hi Yves-Alexis, three years ago you reverted a fix for this bug because using an Alias in lightdm.service seemed discouraged by the systemd maintainers. As can be seen in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=764607#24 they later changed their mind, and going ahead with Alias=display-manager.service would also be part of the fix for #775385, which has been cloned for xdm (#832351), nodm (#852125) and sddm (#848936).
Florian
