I was looking at that too. It seems like schools pages are just WAY out of date. PPIs are no longer offered in the PASS application.
Apparently the PPI was something that some schools required separately from the PEF. You would send it via PASS just like the PEF and it would have them give you scores on a 0-5 scale for 6 key factors like "interpersonal skills" and "professionalism". It was only numbers and it would take like 10 minutes for people to complete.
PPIs disappeared after the 2016 cycle.