| Capability |
| Capable | Plugins which need to expose various implementations of the Composer Plugin Capabilities must have their declared Plugin class implementing this interface. |
| PluginInterface | Plugin interface |
| CommandEvent | An event for all commands. |
| PluginEvents | The Plugin Events. |
| PluginManager | Plugin manager |
| PreCommandRunEvent | The pre command run event. |
| PreFileDownloadEvent | The pre file download event. |