[Makkhdyn]

It seems that it will be

> I'm a firm believer in open source software and open source technologies. I can guarantee you that Light Table will be built on top of the technologies that are freely available to us today. As such, I believe it only fair that the core of Light Table be open sourced once it is launched. At some level, this is an experiment in how open source and business can mix - it will be educational for us all.

Source: http://www.kickstarter.com/projects/ibdknox/light-table