The code was originally based on ExtJS 1.1 and the images and CSS of pre-1.0 versions. This was initially to keep the code under a liberal licence LGPL, and make it usable in commercial projects without fear or concern.
Since then it has been growing and improving, with it's primary focus being intranet application development, and rapid development.
git clone http://git.roojs.org/roojs1
Originally based on the last LGPL code released by ExtJS, this fork has been maintained and extended, to include Universal Constructors, and many new features.