Jari can best answer this.
My thoughts. AFAIK, the "public" PDK has not been available since around 1999/2000. I suspect they discontinued it and support due to economic reasons. There are very few plug-in developers. The PDK is available, if you want to pay the price. Jari uses it in the development of his JW Lua plugin. I doubt it will ever be included in the Finale bundle.
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