@hongminhee洪 民憙 (Hong Minhee) ah I see, seems like it's `markdown-it-texmath` which uses KaTex?
I'm aware that KaTeX is lighter+faster but seen Math folks prefer MathJax. I've also read that MathML (by itself) is not good enough for some cases https://docs.mathjax.org/en/latest/output/mathml.html