it's only a picture, nobody posted a file of it.
Cyberpaddy66 discussed the situation in the comments for the Pepakura file on Deviantart. He also said that he can be messaged on there if anyone has questions or is interested in something (like getting this file), and supplied a link to his Sellfy page with contact information where he can be reached here:
https://sellfy.com/10152962778676556
Did you try contacting him?