You will have to ask the shop. We can only hazard a guess. My guess is: anything from pirate software, OEM builders, VLK, Enterprise, MSDN keys or KMS used.
Certainly won't be legit single use Retail Keys for sale on the cheap.
Illustrator and children's author Owen Davey on maintaining success with his animal and art mastery
WWDC 2019: Dates, what to expect, and how to get tickets
French Days 2019 : dates, sites participants & bons plans