Jack Slocum is one of the best evangelists of YUI, as he gets cool stuff out there that uses YUI. Some of his newer features are not YUI-specific so his YUI-EXT project will become Ext, and will support other libraries.
The most mature User Interface library for web applications will soon support jQuery, the two projects announced today.
Ext, a group of renowned User Interface components including a tree view, live grid, dual-panel layout among others, previously worked as an extension to the YUI library. Beginning with version 1.0 of Ext, it will work as an extension to jQuery as well, allowing jQuery users to leverage the power of the user interface tools available in Ext with the lightweight core library and expressive syntax of the best library for unobtrusive DOM scripting.