This project's docs are way better than zsh.org, that's why. People actually find it informative and use it. Meaning you navigate to it, click around, put it on a side window, and use it while configuring zsh.
It may have better SEO as well, but the main point is that, to rise above the authoritative source, it actually also is performing way better in terms of user metrics.
It may have better SEO as well, but the main point is that, to rise above the authoritative source, it actually also is performing way better in terms of user metrics.