I don't get this file: i just try to make the same fillet inside DesignSpark!
So seems it's now possible for obtain the file in Moi! :)
Sure a little tricky lines command!

I don't know if Vitaly Bulgarov has used DesignSpark or Moi or other ones!)
https://vitalybulgarov.com/about/
Astonishing collection! https://vitalybulgarov.com/3d-kitbash/black-phoenix-full-3d-kitbash-library-20-off-special-offer

Fot this poject seems it's Softimage XSI, ZBrush, Keyshot, Photoshop
http://vitalybulgarov.blogspot.fr/2013/03/black-phoenix-project.html