Scilab is a scientific software package for numerical computations providing a powerful open computing environment for engineering and scientific applications.
Scilab is an open source software. Since 1994 it has been distributed freely along with the source code via the Internet. It is currently used in educational and industrial environments around the world. Scilab is now maintained by Scilab Enterprises: http://www.scilab-enterprises.com/
Note that Scilab has been using code review since 2010 (explaining the diminution in term of number of commits).
