We deal with archives and compressed files everyday. As most open-source projects are distributed in some sort of archive format, users need an unzip utility installed in their computer. The good news is a developer has created a Unity lens that allows you to view the contents of an archive right from the Unity dash.
You need to supply the file path of the archive to preview it. Screenshot:
To install this lens:
sudo add-apt-repository ppa:cwayne18/ppa
sudo apt-get update
sudo apt-get install unity-lens-unzipper