This extension implements a TeX macro with two arguments:
\arialabel{accessible name}{math content}.
This macro allows authors to provide a textual description that provides the accessible name for the enclosed content; in particular, it allows authors to override the heuristics in MathJax's accessibility extension or in other words the heuristics in speech-rule-engine.
Below are two expressions represented with and without the use of this extension. Enable the Accessibility Explorer to see the difference in result.
$$\rm\LaTeX$$ $$\arialabel{LaTeX}{\rm\LaTeX }$$ $$x \times\rlap\Delta\,\Delta $$ $$x \times \arialabel{double struck upper Delta}{\rlap\Delta\,\Delta }$$