you see on the label where it says “extraction grade”?
my understanding is this denatured formulation was made up specifically for this industry to avoid the beverage alcohol tax. [which you can ask for all but $1/gal back if you feel like telling the feds what you’re using it for.]
the question has still come up repeatedly.
I suggest you read a couple of the hits behind Search results for 'heptane denatured' - Future4200
I prefer 190 proof sourced from organic inputs, but I’m a hippy in Eugene. ymmv.
https://www.ttb.gov/applications/manufacturer_nonbeverage_products_packet.shtml