You won't know where it's coming from until you receive it. But given that no other shops have this model, it's likely Newegg. Not sure why they'd send any of their 1070s through Jet though.
To be clear, Jet.com is just a clearinghouse. They stock no products and ship no merchandise. All of the items they list are actually inventory of partner retailers, like Newegg, or more often 2nd-tier stores and distributors, which ship the products to you directly.
I've purchased a bunch of items from Jet.com. Only one, a G.Skill RAM kit, came from Newegg. Everything else was from unknown outfits that often have no consumer-facing website.