I’m pretty sure mathbox got abandoned when mathbox2 came out (understandably, it’s mostly one guy building it). But then mathbox2 appears to be abandoned now, and last time I tried to use it (a couple years ago) the coffeescript would no longer compile.
It was a really visionary piece of work, it’s a bummer to see it fall apart like this, and I don’t think anything has come out since that really replaces it (though manim does look cool).