Interface for Package Manager UI Extension.
| Method | Description | 
|---|---|
| CreateExtensionUI | Creates the extension UI visual element. | 
| OnPackageAddedOrUpdated | Called by the Package Manager UI when a package is added or updated. | 
| OnPackageRemoved | Called by the Package Manager UI when a package is removed. | 
| OnPackageSelectionChange | Called by the Package Manager UI when the package selection changed. |