What a weird package.
You'd think they'd mimic the usual SO-8 pinout, or at least put more than one pin for source connection. But then again that might not be necessary for the target ID.
It is weird indeed, but hey, this all contributes to our knowledge and ongoing knowledge of electronics , doesn't it ?
Sometimes i sit and wonder... Beginners coming into the industry need to have a knowledge of parts that goes back to the 60s,
Now i've been into electronics since the 70s and naming conventions have changed a lot for some things and not so much for others
but you're right, one would think they would just go with the SO-8 convention