Thank you for taking an interest in iris. Feedback of any kind is welcome, and so are stories about where it worked and where it didn't.
The best way to contribute is to file an issue for a bug or a feature request. Include all the details: what you ran, what you expected, what happened instead, your OS and architecture, the iris -version output, and, for tunnel problems, the output with -v.
You may open a pull request. Keep it small and focused, say what it does and why, and expect that it may take some time to be reviewed and merged. Opening an issue first is a good way to check whether a change fits before you spend the effort.