Can anyone lead me to "PDM Enablers specification" (for Effectivity)?

Trying to learn more about the APIs for managing(mainly CRUD operations on) Effectivity in Windchill 9.1, and I keep coming across references to "PDM Enablers specification", yet can't find that anywhere in the PTC site, knowledgebase, or manual set I have.

Can anyone help - what is this specification - does it exist, and if so where can I find a copy?

Thanks for any & all leads!!