CyberCat - Free internet application and framework written in Cocoa for Mac OS X
Version: 0.9 AlphaCyberCat is a free internet application and framework written in Cocoa for Mac OS X.
Operating System: Mac OS X
CyberCat is completely plugin-based: instead of implementing protocols, renderers, or interfaces in the core application, they are implemented in completely self-contained plugins.
Plugins are Mac OS X Bundles, written in Objective-C. The framework is very easy to use, and it will be documented soon (but until then, it shouldn't be hard to figure it out by looking at the source of existing plugins).
The result of all this is that anyone who knows Cocoa can add a whole new unit of functionality to the program - a protocol, an interface, a renderer, or even a plugin that just adds or modifies other functionality.
All this without ever having to touch the original source code (though you are of course encouraged to do so for reference).
NOTE: CyberCat is still under development, and is currently in the "alpha" development stage.