My mistake, I saw API SJ in the ESP literature and my mind immediately went to diesel spec, as in CJ-4 (not S).
Last time I bought ESP the bottle referenced low emission diesel technology, DPF and such in a way that I came away thinking it was developed for use in light duty diesel engines. I recognize it's dual rated however, as are most diesel oils.
Not saying there aren't thick 30 weight oils out there, there's certainly plenty of European and diesel stuff available.
But I was surprised to see a modern (SP rated) PCMO that's gotten thicker when the trend over the past 20+ years has been going the other direction. Correct me if I'm wrong but this oil carries none of the major European certs or diesel ratings.