| IExtensions | A model object that contains the portion of the plug-in model
 responsible for extensions and extension points. | 
| IExtensionsModelFactory | This factory should be used to create
 instances of the extensions model objects. | 
| IFragment | A model object that represents the content of the fragment.xml
 file. | 
| IMatchRules | This interface contains constants used throughout the plug-in
 for plug-in reference matching. | 
| IPlugin | A model object that represents the content of the plugin.xml
 file. | 
| IPluginAttribute | An attribute of XML elements found in the plug-in. | 
| IPluginBase | A model object that represents the content of a plug-in or
 fragment manifest. | 
| IPluginElement | Classes that implement this interface model the
 XML elements found in the plug-in model. | 
| IPluginExtension | Classes that implement this interface model the extension
 element found in the plug-in or fragment manifest. | 
| IPluginExtensionPoint | Classes that implement this interface model an extension point
 element specified in the plug-in manifest. | 
| IPluginImport | Objects that implement this interface represent references
 to required plug-ins. | 
| IPluginLibrary | The class that implements this interface represents a
 reference to the library that is defined in the plug-in
 manifest. | 
| IPluginModelBase | This type of model is created by parsing the manifest file. | 
| IPluginModelFactory | This factory should be used to create
 instances of the plug-in model objects. | 
| IPluginObject | A base interface for all the objects in the plug-in model. | 
| IPluginParent | Classes that implement this interface are
 capable of containing other plug-in objects. | 
| IPluginReference | Objects that implement this interface represent references of
 plug-ins. | 
| ISharedExtensionsModel | This type of model is created by parsing the plug-in
 manifest file but only takes the extensions and extension
 points into account. | 
| ISharedPluginModel | This type of model is created by parsing the manifest file. | 
| ModelEntry | A ModelEntry object has an ID and keeps track of all workspace plug-ins and target
 plug-ins that have that ID. | 
| PluginRegistry.PluginFilter | Filter used when searching for plug-in models. |