Yeah that's a good point regarding publishing binaries. I would guess that he wants to keep tight quality control (since in the past there were crap binaries being passed around). But yes I don't consider it GPL compatible, but it (was, see below) close enough for me ¯\_(ツ)_/¯ (I try not to let perfect be the enemy of good).

That said I just tried to build it for the first time (wanted to make a small improvement) and there are no documented build steps and a standard ant build doesn't work. There are open github issues where the author is very dismissive and just says basically "code not supported, just for educational purposes."

I poked at it for about 15 minutes but I've never used ant before and couldn't get the build working. That really saddens me. Unless things improve I won't be renewing my subscription. I'm pretty disappointed to say the least.