We are always very happy to have contributions, whether for trivial cleanups or big new features. We want to have high quality, well documented codes for each programming language, as well as the surrounding ecosystem of integration tools that people use with Apache RocketMQ.
Nor is code the only way to contribute to the project. We strongly value documentation, integration with other project, and gladly accept improvements for these aspects.
We have a few mailing lists hosted by Apache, please refer to here for more details.