From Learn About the Ext JavaScript Library

To make sure that User Extensions don't cause conflicts with the official code there is a special namespace for User Extensions:

Ext.namespace('Ext.ux');

Currently used are:

Contents 1 Collapsible InfoPanel/Accordion 2 Navigation MenuBar 3 Tag Cloud 4 CodePress

Collapsible InfoPanel/Accordion

Ext.ux.InfoPanel
Ext.ux.Accordion
Ext.ux.InfoPanel.GoogleSearch

Navigation MenuBar

Ext.ux.Menubar

Tag Cloud

Ext.ux.TagCloud

CodePress

Ext.ux.CodePress