Yes, I'm pretty sure it's that aria label. The first line of this code.

    <span class="katex-html" aria-hidden="true">
        <span class="base">
            <span class="strut" style="height:0.6444em;"></span>
            <span class="mord">2</span>
            <span class="mord mathnormal" style="margin-right:0.03588em;">π</span>
        </span>
    </span>

My first inclination was to simply run `say` on my Mac comamdn line and paste the line in. That read it correctly. The other commenter called out the `aria-hidden` attribute and I'd guess that's it. It's explicitly hidden.

Apparently this is all intentional as outlined in this bug report.

https://github.com/KaTeX/KaTeX/issues/38