[runarberg]

Nice demo. I don’t have access to a mac so I can’t see this in Safari, but using Firefox I can immediately spot there are some kerning mistakes in the MathML rendering which are not present in MathJax rendering.

However, isn’t that just the fact the the default math font (DejaVu Math TeX Gyre in Firefox i-on Ubuntu) is not good enough? I use Libertinus Math in my own little demo page (https://runarberg.github.io/mathup/) and it looks just fine (IMO). The only think to note is that TeX Gyre is so pervasive (as it is the default [only?] MathJax font) that it takes a bit getting used to other math fonts on the web.

For example here is the Iglalia example from your demo page displayed with Libertinus Math in Firfox (https://imgur.com/q3QuJOA). The same example has some issues in your demo page with DejaVu Math TeX Gyre