I have a theory:

The creator dropped hints by way of what was not said.
 referencing consecutive keys from a " deterministic wallet "  can be a set
of keys derived in any deterministic way you can come up with. My point is he specifically omitted any reference to bip32 , bip39 etc.
 
.. if a formula for key generation ( aka derivation ) is indeed discovered, then the formula itself satisfies the claim of being "from a deterministic wallet"
 Surely, key derivation by any means resulting in a predicted  value, qualifies as deterministic. Note nothing is said about using ecdsa either. . .
    Secondly, take another look at the creators name:  "saatoshi_rising";  is the "a" metaphore for a funtion that calls for a duplication  or split at byte 2 in some schema / used as padding etc  to fill in a 4 byte box , "_" being some sort of operator Or hinting at specific obscure maths? or a clever reference to double float precision ?

 Could  saatoshi_rising =
           doouble_float ?                What do you think?