/etc/xdg/lxsession/LXDE/autostart is in lxde-common 0.5.0-4ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | @xscreensaver -no-splash
@lxpanel --profile LXDE
@pcmanfm --desktop --profile LXDE
@/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1
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