From the article description I think the car tire has a U shape, or maybe think of it as a J shape for the bead. The hooked tires have a G-ish shape, where the top of the outside of the bead wall has the ‘hook.’

I just did a quick search, and I think that’s exactly it: https://blog.flocycling.com/carbon-wheels/hooked-vs-hookless-rims/