On the May 7th Lorecast, Richelle confirmed that yes there is a new promo classification that could be seen on the promo cards previously revealed with the Beast Gift Box and Collection Starter Set: Rapunzel Edition products. This new classification is "PD" instead of the usual P plus a number.
"Cards that are promos through product are going to have that PD Collection number now so that they kinda feel like a full collection on their own, separate from other promo sets." - Richelle from Ravensburger
This change is intended to organize promo cards into distinct sets, making it easier for collectors to pursue and complete specific promo collections rather than having all promos grouped under broad classifications like P1, P2, etc. This should also make organizing and tracking individual collections much easier.
In this case "PD" stands for Product and we should expect to see this revision with some other classifications of promo cards as well.
Source: Lorecast Twitch Clip