empheq is missing

[ickc]

Under es5/input/tex/extensions, empheq.js is missing.

c.f. mathjax/MathJax-docs#290

[dpvc]

Thanks for your report. It turns out that the build file for empheq and cases put the packed file into the wrong location. I will make a pull request to fix it, but in the meantime, you can use the configuration

MathJax = {
  loader: {
    source: {
      '[tex]/empheq': 'https://cdn.jsdelivr.net/npm/mathjax-full@3/components/es5/empheq.js',
      '[tex]/cases': 'https://cdn.jsdelivr.net/npm/mathjax-full@3/components/es5/cases.js',
    }
  },
};

to access these components.