The OpenModelica Compiler is the core of the OpenModelica project, which is an open-source Modelica-based modeling and simulation environment intended for industrial and academic usage.
Contributions are primarily in the form of pull requests. Note that your contributions are assumed to follow the contributior license agreement (which means the Open Source Modelica Consortium holds the copyright).
Commits that are pushed to this repository should pass the test suite, and @OpenModelica-Hudson makes sure this is true. Developers should push their changes elsewhere and use the OpenModelica hudson job to trigger a build+push (it can build from a given URL+branch or a specific pull request, as desired). It is recommended to use a feature branch for pull requests since hudson may rebase them, which in turn would make it harder to merge the changes.
There are Linux instructions available.