The procedure to contribute: https://www.keypop.org/community/contributing/
The source code of the Eclipse Keypop project is hosted on GitHub. The Eclipse Keypop organization lists all the repositories of Keypop components: https://github.com/eclipse-keypop/
GitHub Organization
You can use the code from these repositories to experiment, test, build, create patches, issue pull requests, etc.
eclipse-keypop - Project repository hosted on GitHub.