In this repository you can find the documentation and wiki for the HeadsPluginAPI plugin
Here is a link to the wiki, which will explain how to use HeadsPluginAPI: https://github.com/CC007/HeadsPluginAPI/wiki
You can download the javadoc jarfile for this plugin here: https://cc007.github.io/HeadsPluginAPI/v3.0.0/HeadsPluginAPI-3.0.0-javadoc.jar
If you want to look through the javadoc online, click here: https://cc007.github.io/HeadsPluginAPI/v3.0.0/apidocs/