The developers of EXT 3.0 have gone through the code, stripping out everything except for the core functionality, optimised the code and gzipped it to bring it down to a modest 25kb in size. They have also changed the licensing to use the MIT License (which drew some ire from some developers but was generally accepted by the majority).

Some of the features of EXT Core 3.0 are:

• DOM manipulation and traversal
• CSS management
• Event handling
• Dimensions and Sizing
• AJAX and JSON Support
• Animations
• Classical Inheritance Class System
• Observable Class
• Markup generation and Templating
• Timed code execution
• URL encoding and decoding

EXT Core 3.0 Beta core functionality contains:

• Carousel
• Lightbox
• Menus
• JSONP
• Simple Tabs

For those of you that need more extensive features, then EXT 3.0 is more your ticket. However, for anyone else who needs to put together a lightweight interface that has the Web 2.0 look and feel, then EXT 3.0 Core is definitely worth looking at.

For more information: EXT Core 3.0 Beta