Ext.ux.upload was originally created by Harald Hanek (github.com:harrydeluxe) and is available from
https://github.com/harrydeluxe/extjs-ux.git
For ExtJS 4.2.1 support the fork by Nikolai Babinskyi (github.com:babinik) was used https://github.com/nbabinski/extjs-ux.git 9837ab6 [nbabinski/master] form status bar - use itemId instead of id cfg option
resources/lib/plupload is also from this repo