Defines the basic interfaces for a plugin. These interfaces are inherited by the core class of a plugin. The core class of a plugin is then the one that will be notified the activation/deactivation of a plugin via the activate/deactivate methods.
For simple (near trivial) plugin systems, one can directly use the following interfaces.
In your own software, you’ll probably want to build derived classes of the IPlugin class as it is a mere interface with no specific functionality.
Your software’s plugins should then inherit your very own plugin class (itself derived from IPlugin).
Where and how to code these plugins is explained in the section about the PluginManager.