The application note refers to standard and triple insulated magnet wire. You find specifications of insulation strength in more detailed data sheets, which should be searched at magnet wire manufacturers not at catalog distributors. Together with the polyester tape layers, there's a rather complete description how to make the transformer. There are open points like the magnet wire temperature class. Without further specifications, I would expect lowest grade of standard polyurethane insulated magnet wire.
But it's a professional application note addressed to skilled engineers, not a DIY instruction. Some knowledge is taken as granted.
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Here's a datasheet explaining the grade 2 specification **broken link removed**
You find more information on the product pages **broken link removed**