Yes! I've been experimenting a LOT with kona.* K seems more my style, but I'm really excited about J being opened too! The APL family is way too interesting to have it confined by extremely expensive licenses and niche industries.

* Also, from communicating with the author: it's a clean re-implementation based on experience with it, not an open-sourced version of "real" K. (I've never used K or Q.)

I got the '93 J to work, too (on OpenBSD), but it's evolved a lot since then, and having the official version open will draw a lot more attention.

Also, thanks for answering some of my questions about J, K, and valence/rank a while back.