You can use the code from these repositories to experiment, test, build, create patches, issue pull requests, etc.
https://github.com/jakartaee/inject - Project repository hosted on GitHub.
https://github.com/jakartaee/inject-spec - Project repository hosted on GitHub.
https://github.com/jakartaee/inject-tck - Project repository hosted on GitHub.
https://github.com/jakartaee/cdi - Project repository hosted on GitHub.
https://github.com/jakartaee/cdi-tck - Project repository hosted on GitHub.
https://github.com/eclipse-ee4j/cdi-tck-cpl - Project repository hosted on GitHub.
https://github.com/eclipse-ee4j/cdi-cpl - Project repository hosted on GitHub.