Technically the blockchain that would be referred to in the GP is more than just a data type. It would also include the algorithm for deciding the next block of

Technically the blockchain that would be referred to in the GP is more than just a data type. It would also include the algorithm for deciding the next block of valid transactions. I think the reference is supposed to imply that the consensus mechanism built into the system is responsible for dictating the validity of a transaction as opposed to a human.