/etc/xdg/autostart/gnome-user-share.desktop is in gnome-user-share 3.0.4-0ubuntu1.
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 8 9 10 11 12 | [Desktop Entry]
Name=Personal File Sharing
Comment=Launch Personal File Sharing if enabled
Icon=folder-remote
Exec=/usr/lib/gnome-user-share/gnome-user-share
Terminal=false
Type=Application
Categories=
OnlyShowIn=GNOME;Unity;
X-GNOME-Autostart-Delay=15
NoDisplay=true
X-Ubuntu-Gettext-Domain=gnome-user-share
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