This is a copy of the "zen-grids" extension.

It now overrides the original which was found here:

/Library/Ruby/Gems/1.8/gems/zen-grids-1.4

Unpacking an extension is useful when you need to easily peruse the
extension's source. You might find yourself tempted to change the
stylesheets here. If you do this, you'll find it harder to take
updates from the original author. Sometimes this seems like a good
idea at the time, but in a few months, you'll probably regret it.

In the future, if you take an update of this framework, you'll need to run

    compass unpack zen-grids

again or remove this unpacked extension.