This theme is currently used by this site. The file contains part of ExtJS library v.2.2.1. ExtJS themes included: default, gray ans slate, purple (by madrabaz), 2brave and lite. In short, this theme is: advanced, clean, fluid width, two-column; with look&feel of web applications made with ExtJS library using the above link. This is ExtJS WordPress Theme version 2 released under GPL v.3 (the same as ExtJS library).
Ext WordPress Theme v.1.9
The file contains part of ExtJS library v.2.2.1 that is resource directory with CSS files and images. ExtJS themes from the ExtJS distribution are default, gray ans slate. It also contains purple ExtJS theme by madrabaz (you can check it here). There are two more ExtJS themes made by me: 2brave and lite. The theme is released under GPL v.3 (the same as ExtJS library).
Ext JS WordPress Theme v.1.0.1
The release of Ext JS WordPress Theme v. 1.0.1 contains a distribution of Ext JS library 1.1.1. Both, the theme and the library are distributed under LGPL v.3 license. To apply the theme to your WordPress installation do what you usually do with themes: unpack it to wp-content/themes/ directory, and activate it using WordPress administration interface. This should be enough.
2brave ExtJs 2.0 Theme
This is just a preview. No license.
Note: This is not WordPress Theme. This is stylesheet for ExtJS applications. For more details check here.