AaronH is pretty happy about the way requirejs is organized on kb and isis, after long efforts.
He forked the requirejs-rails gem to upgrade it, as it was unmaintained, on https://github.com/aar0ntw/requirejs-rails
It mainly enables to integrate requirejs in the rails4 assets pipeline, by pre-compiling files with r.js. If you want to know more about it, feel free to bug him. And, be nice, go star his repo !