What kind of kale is used in this salad?

If you are asking because of the way it looks in the photo- I think it's a sort called Cavalo Nero, or Lacinato, aka Dinosaur kale. Might also be a sort called Black Magic, which is about as mild as the kales come. But as Nancy stated, you can use what you prefer or can find in the market. I'd go with a young kale myself, so it didn't overwhelm the peaches and apricots- but that's me.

As the recipe doesn’t specify, you can use any you prefer or can find in your local markets.

Personal preference - I like organic full growth or baby kale (regular or organic) as the two varieties I find best in taste and texture.