/usr/share/xsessions/lightdm-xsession.desktop is in lightdm 1.10.3-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | [Desktop Entry]
Version=1.0
Name=Default Xsession
Exec=default
Icon=
Type=Application
|