The Treedix will tell you that, as it is a feature of the eMarker chip (no chip means 60W).
Assuming the chip isn't fraudulently added. Like in the article, some manufacturers are shady & will sell cables with e-marker chips for capabilities the cable can't actually support.
alt Hacker News
Assuming the chip isn't fraudulently added. Like in the article, some manufacturers are shady & will sell cables with e-marker chips for capabilities the cable can't actually support.