One has to decide whether they are running a raceway with conductors or a cable. They don't have to mark the individual type of conductors in the cable - the cable type designates how they are treated no matter what they may actually be. NM cables are also to be treated as 60°C conductors for ampacity. THHN/THWN is probably about most common conductor made so they just use it when making these cables, they just don't mark the conductors like they do when making THHN/THWN intended to be sold as THHN/THWN."They are THHN/THWN but they are not designed to be used without the outer jacket. This is a dry location only product."