Developers points are a one time promotional "gift" of points owned by
DVC, offered as an incentive for purchase. Either they are unsold points in new resorts, or may be points acquired through loan default/foreclosure or through exercising Right of First Refusal on a sale.
Current developers points can only be used at SSR,
Disneyland, or possibly for an RCI trade. They can be used to book stays at SSR 7 months from schedulaed arrival, and must be used by a date specified in your contract. They can not be banked or transferred, but they can be used for a rental reservation.