How to set gnome-classic as default session for all users in gdm3 (system-wide setting)? I'm using Debian Jessie with GNOME 3.12.
I've tried creating fake gnome.session in /etc/xdg/gnome-session/sessions that launches gnome-classic and searched for relevant gdm3 setting but to no avail. Solutions I've found online seem to work only for older GNOME versions.