The Extension Manager provides an easy and convenient way to install and delete extensions in Adobe applications,and to find information about extensions you installed. It also provides a convenient way to navigate to the Adobe
Exchange site. You can find more extensions, get information about extensions, and rate extensions that you used.
If you haven't already installed Extension Manager CC, click Help > Manage Extensions in your application to download and install Extension Manager automatically.
Please check : https://helpx.adobe.com/pdf/extension_manager_reference.pdf