/etc/xdg/autostart/cellwriter.desktop is in ubuntu-mobile-default-settings 0.11.
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 7 | [Desktop Entry]
Name=CellWriter
Comment=On screen keyboard
Exec=cellwriter --dock-window=1 --keyboard-only --hide-window
Terminal=false
Type=Application
X-GNOME-Autostart-enabled=true
|