"Our founders and engineers have a strong open source background and we consider a contributory relationship with the FOSS community as the normal course of business. Thus, our plan all along has been to make our entire client-side code base open source; however, as anyone who has worked with such issues knows, it is often not quite that simple."

So they say they want to be good, but not quite yet. I've posted a question about nimbus.io on that page.