Edit: now there is an R package for server-side MathJax rendering, katex by Jeroen Ooms.
Whilst I most certainly do not write LaTeX formulas on the regular anymore, I got curious about their MathJax rendering on websites.1 In brief : your website source contains LaTeX code, and the MathJax JS library (self-hosted or hosted on a CDN) transforms it into something humans can understand: some …