Which is the case here for Graal (there are differing definitions of "free"). From your link: > While most proprietary software is distributed without the sour

Which is the case here for Graal (there are differing definitions of "free"). From your link: > While most proprietary software is distributed without the source code, some vendors distribute the source code Source code available, or even under an open source license, does not change whether it is proprietary. Not sure this is the best place to discuss the nuances of these terms. Essentially, they retain the IP, have shown a willingness to go after those doing things like re-implementing it, and in general should give people pause about using tech owned by them.