/usr/share/mythbuntu/lightdm/lightdm.conf is in mythbuntu-lightdm-theme 1.01.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | [SeatDefaults]
user-session=mythbuntu
allow-guest=false
#autologin-user=
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