Why can't it be simply a rye-based cereal mash distilled to 190 proof? It's rye mash, but not whiskey from rye mash because i) never put in wood, ii) 190 proof or over as opposed to under 160 (would go the argument). What I'm wondering is if the stuff being aged in new charred oak is typical rye white dog but they chose to distill some of the same stuff higher for this limited release.
Or, maybe it is a mix of some rye-based GNS and some rye white dog.
190 proof spirit can be pretty impactful, it only acquires truly neutral character as vodka and that requires more than maple charcoal leaching.