I did a bit more digging.
It seems that the plesk-application-vault package is a metapackage for ALL of the applications in the APS catalog.
xxxxx:/opt/archive# aptitude show plesk-application-vault
No current or candidate version found for plesk-application-vault
Package: plesk-application-vault
State: not a real package
Provided by: ppwse, psa-appvault-advancedpoll, psa-appvault-anyinventory, psa-appvault-articlepublisher, psa-appvault-autoindex,
psa-appvault-avactis, psa-appvault-b2evolution, psa-appvault-bbclone, psa-appvault-brim, psa-appvault-coppermine,
psa-appvault-cs-cart, psa-appvault-cslh, psa-appvault-cubecart, psa-appvault-docfaq, psa-appvault-dolphin, psa-appvault-drupal,
psa-appvault-easybiller, psa-appvault-easysnaps, psa-appvault-egroupware, psa-appvault-emuwebmail, psa-appvault-eswap,
psa-appvault-gallery, psa-appvault-geeklog, psa-appvault-gtchat, psa-appvault-helpcenterlive, psa-appvault-joomla,
psa-appvault-knowledgetreeoss, psa-appvault-mailer, psa-appvault-mambo, psa-appvault-mantis, psa-appvault-mediawiki,
psa-appvault-merchant, psa-appvault-moodle, psa-appvault-movabletype, psa-appvault-multicart, psa-appvault-myorgbook,
psa-appvault-noahclass, psa-appvault-nucleus, psa-appvault-onebiz, psa-appvault-openbiblio, psa-appvault-oscommerce,
psa-appvault-osticket, psa-appvault-owl, psa-appvault-phpads, psa-appvault-phpbook, psa-appvault-phpbugtracker, psa-appvault-phpdig,
psa-appvault-phpmoney, psa-appvault-phpmyfamily, psa-appvault-phpmyvisites, psa-appvault-phprojekt, psa-appvault-phpsurveyor,
psa-appvault-phpwebsite, psa-appvault-phpwiki, psa-appvault-pinnacle-cart, psa-appvault-plog, psa-appvault-pmachinefree,
psa-appvault-postnuke, psa-appvault-ray, psa-appvault-serendipity, psa-appvault-siteframe, psa-appvault-smf, psa-appvault-socialware,
psa-appvault-ssm, psa-appvault-sugarcrm, psa-appvault-supportcenter, psa-appvault-supportdesk, psa-appvault-tellme,
psa-appvault-tikiwiki, psa-appvault-tutos, psa-appvault-typo3, psa-appvault-uebimiau, psa-appvault-vivvocms,
psa-appvault-webcalendar, psa-appvault-webshopmanager, psa-appvault-wordpress, psa-appvault-xoops, psa-appvault-xrms,
psa-appvault-xtcommerce
xxxxx:/opt/archive#
So if I actually installed this, it would install ALL packages from APS which I do not want.
Is my understanding of this correct?
Thanks