STINGER is available under the BSD license for you to use and hack on as you see fit. We encourage discussion via GitHub to accept any feedback, requests, and code that you wish to contribute. The current development version of STINGER is hosted on github.com.
The Developer Guide provides the guidelines for how to get involved with STINGER. STINGER uses a pull request model similar to the git-flow model to review and accept new features and patches. Issues and bugs should be posted to the github issue tracker, and one of the developers will respond. Also questions can be asked via StackOverflow and the developers will try to answer.