openutils-mgnlext is simply a distribution of extjs for usage into magnolia.
The standard ext resources (js/css/images) are packaged in the jar inside the "mgnl-resources" folder, so that they are available using the ".resources" path in magnolia. You can simply add a dependency on openutils-mgnlext instead of copying all the extjs resources in the webapp folder or in your custom modules.
The packaged version of extjs is 2.1. The license (GPL) is the same as ext, since this module doesn't contain anything more than the standard ext distribution.