You can find a list of technologies/frameworks supported by an extension in Covered Technologies. You can also find a full set of documentation for extensions here.
In an upgrade scenario (i.e. from upgrading from one release of CAST AIP to another) when installing the new release of CAST AIP, there is no need to re-install any extensions you were using with the previous release of CAST AIP.
Note that in CAST AIP 8.3.0x, several official CAST AIP extensions are shipped with the setup and are installed by default with all new CAST AIP triplets. It is not possible to choose not to install them: