Quartz Desktop Description:
Quartz Desktop allows you to view Quartz Composer Composition (.qtz) files on your desktop in Mac OS X 10.4.
What's a Quartz Composition? Quartz Compositions are screensaver-like files that can include rich data sources and render them using all the features of Quartz Extreme and Core Image. The best example is the RSS screensaver that ships with Tiger.
Operating System Support: Mac OS X 10.4 or higher, Tiger compatible, Developer Tools (optional)