I did not buy the optional Application Vault package, however I've got a whole slew of components installed in /usr/local/psa/var/cgitory. How do I access or add to them from the Plesk Control Panel? Do I actually have to BUY the Application Vault license with those 30 components just to use the App Vault functionality in the CP?

I've already got 33 components installed, how do I get to them?

 

Yes, if you wish to use the Plesk control panel interface for installing/managing those packages, then you need to purchase the additional key license from Plesk.

Other options are to purchase/use another App manager such as 4PSA's Integrator product, or to install apps manually from the SSH command shell prompt.

The reason the files are present is that the Plesk installer automatically downloads them so that if you have the App Vault key, the files will be ready to go.