This was filed upstream: https://secure.phabricator.com/T6609 and a community member published a prototype implementation: https://github.com/ProfFan/phabritex
I intend to try out the extension and asses what, if anything, is needed to make it work well with Phorge. Maybe all we need to do is link to it prominently if it's working well with Phorge.
I see that it depends on a NodeJS external script (server-side).
Maybe we can hammer similar backends instead:
There is also MathJax, a subset of LaTex that only covers the mathematical notation without the page layout functionality.
edit: also, the similar project, https://github.com/KaTeX/KaTeX
Interestingly, I just discovered Wikimedia has a pretty cool project to render math on the server side, by transpiling some js into php:
https://phabricator.wikimedia.org/T302628
We might be able to incorporate that instead of MathJax/KaTeX.
Looks like that depends on MathJax.js to do the math part client side, so probably not useful.