Please help me understand PSA POP Reports/Player Registry Checklists

[The Detroit Collector]

The PSA registry is created by regular individuals like you, who want to start a registry for their collection if there is not one already.

For example.
There is not a registry for M101-2s. PSA does not grade them, but we will use it as an example.
If PSA did grade these supplements, I would put in a request to add this registry to PSA along with its information.

Once it has been added, if there were supplements missing or recently found, anyone could put in a request to add this supplement to the registry.

Another example, there is a Detroit Tigers Hall of Fame PSA registry. When I started the set, I noticed that Pudge Rodriquez was not in the set registry, even though he played for Detroit for 5 years. I put in a request to add his rookie card to the registry. After some time, the card was approved by PSA and Pudge is not a requirement for the set registry.

Where I'm getting at is, all sets are created different. They are created by people like you and I and can be updated at any time.