but this does not mean zone 2 (necessarily). Rough guess, FTP ~ 80% VO2max. 75% VO2max somewhere upper tempo. This is not zone 2. And I don’t think he means it as zone 2 in the context.
@tshortt has mentioned the critical points. Training in range close to fatmax. Lab testing is part of his system, he uses fatmax and lactate as cues. It is clearly not “I saw this elite norwegian xc skier walking up a hill” pace.
I find this a very interesting trainig model, clear guidance with just a few words. No bla bla, straight to the point. If you want to improve an area you have to stress it. Hence, at fatmax/AeT/LT1.