See also: https://mathics.org/
It's a more mature and complete reimplementation of Mathematica, though still miles behind the original.
https://github.com/Mathics3/mathics-core/graphs/contributors
The project seems to have had a decent level of contributions for the last couple of years.
See also: https://mathics.org/
It's a more mature and complete reimplementation of Mathematica, though still miles behind the original.