The lead developer up until 2 years ago, Angus Griffith's LinkedIn says he's at Google. [0]
In April 2016, Angus replied to a comment of mine "Mathics is still maintained. There are currently two of us working on it. The last release was v0.9 in March this year." [1].
The original creator Jan Pöschko's GitHub profile states "JavaScripter making the notebook interface of wolframcloud.com" [2]. His bulk contributions to Mathics stopped in 2012, but he still makes sporadic contributions to Mathics - see here he merged a pull request March 2019 [3] - suggests Wolfram tolerate the existence of Mathics because it's not a serious threat.
As the creator of Sage, what's your opinion of the legal risks of creating a Mathematica syntax compatible clone like Mathics in the light of Wolfram Research's fairly aggressive assertion of its IP "rights"?
[0] https://www.linkedin.com/in/angus-griffith-093433b0/
[1] https://news.ycombinator.com/item?id=11465064
[2] https://github.com/poeschko
[3] https://github.com/mathics/Mathics/commits?author=poeschko&s...