Documentation for plugininterface.dll

Hi,
IS there a documentation for plugin developpement available ? Am I missing something ? I found a complete documentation for macro writting (as well as screenscren developpement), but nothing about plugininterface API.
IS there a documentation for plugin developpement available ? Am I missing something ? I found a complete documentation for macro writting (as well as screenscren developpement), but nothing about plugininterface API.