There are four mailing lists, available from the SourceForge project mailing list page.
If you encounter something that you think isn't working right, you should file a bug report on the SourceForge project bug tracking page. Please browse the existing bugs first to make sure you're not submitting a duplicate.
If you don't have a bug, but Chromium doesn't do something you think it ought to, you can submit a feature request on the SourceForge project feature request page. Feature requests will (obviously) be lower priority than bugs, but they'll all be taken seriously. Of course, if you have a feature request, you could give thought to implementing it yourself if you have the resources. This is an open-source project, after all. Feature additions may be rolled into the main source tree on a case-by-case basis.