This is a plugin for Piwik that generates reports about the IPv6 reach of your websites. It is written as a tracker plugin and directly hooks into the Piwik tracking call.
I wrote an article about the development that lead to this plugin and explained how the plugin works internally. You can find the article at Geekmonkey
There is also a short article that explains how to setup the plugin.
If you are interested in contributing to this plugin, feel free to send pull requests or create issues.
GPLv3 or later