What is TargetEnvironment=Unity?

Question

I have a pure Lubuntu 12.10 installation. While looking at some .desktop files in /usr/share/applications I see TargetEnvironment=Unity.
One example is in the .desktop file for Google Chrome:

[NewWindow Shortcut Group]
Name=New Window
Exec=/opt/google/chrome/google-chrome
TargetEnvironment=Unity

[NewIncognito Shortcut Group]
Name=New Incognito Window
Exec=/opt/google/chrome/google-chrome --incognito
TargetEnvironment=Unity

Another example is the .desktop file for Inkscape:

[Drawing Shortcut Group]
Name=New Drawing
Exec=inkscape
TargetEnvironment=Unity

To find out what that means, I looked at Desktop Entry Specification - freedesktop.org standards and at UnityLaunchersAndDesktopFiles. But neither mentions TargetEnvironment. Hence my question.

Answer 1

TargetEnvironment makes the Shortcut Group (i.e. quicklist item) open only in Unity environments. You could also use the OnlyShowIn=Unity keyword.

Here's an old Launcher tutorial that mentions it.

As of here TargetEnvironment is deprecated.