/usr/share/app-install/desktop/gnome-tweak-tool:gnome-tweak-tool.desktop is in app-install-data 14.04.0.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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X-AppInstall-Package=gnome-tweak-tool
X-AppInstall-Popcon=1912
X-AppInstall-Section=universe
Name=Tweak Tool
Comment=Tweak advanced GNOME 3 settings
Icon=gnome-tweak-tool
Exec=gnome-tweak-tool
Terminal=false
Type=Application
StartupNotify=true
Categories=GNOME;GTK;Settings;
Keywords=Settings;Advanced;Preferences;Extensions;Fonts;Theme;XKB;Keyboard;Typing;
OnlyShowIn=GNOME;Unity;Pantheon;
X-Ubuntu-Gettext-Domain=app-install-data
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