Tex.sx has a tag for questions that is named
wiki and currently has this description:
Topics linked to usage of TeX in wiki-type websites, such as Wikipedia.
Wikipedia (run by Wikimedia, running on Mediawiki software) has long been using mathmode syntax inside
<math> elements for generating formulas in articles. The exact way this has been parsed (client-/server-side MathJax, OCaml texvc, texvcjs, Mathoid) and displayed (source code, MathML, PNG, SVG) has differed over time and may depend on browser capabilities and user settings.
However, it basically supports all of plain LaTeX plus AMSmath.