Yes, it's also clear for me.
I think the tutorial is confusing things by distinguishing between
- Toroidal current transformers
- Bar-type current transformers
altough they are described with an almost identical setup, a straight conductor through the core center. If you read the description thoroughly, you see that "no winding" is also described as a current transformer that "uses the actual cable or bus-bar of the main circuit as the primary winding, which is equivalent to a single turn".
So whatever you describe as a winding or no winding, it uses a single turn.