No, it's 3D. It's some kind of automatic background removal. You can see this falling apart in my comment: https://news.ycombinator.com/item?id=42252127
That "outline" is just an artifact of less-than-perfect removal. Here's another one: https://imgur.com/a/zTQubPb
3D in what sense? You think they're doing actual mesh generation?
Misunderstood your comment. It is 2D as you've said, my above being evidence of that.