ARIA Live region (aria-live="polite"): image's alt texts are not announced by screen reader

[jmuheim]

I think it's wonderful that Reveal.js announces slide contents to screen readers using an aria-live region. I first thought that the whole slide is such a region, but then I realised that there's a dedicated visually hidden <div aria-live="polite"> which is fed with the current slide's contents manually. Fair enough, as long as it works, this looks solid and reasonable!

But then I realised that images aren't announced at all through this mechanism. Here the alt value is "Abbildung 2":

But this isn't fed to the ARIA Live region:

Probably alt-texts aren't treated as "real" content, which is a shame. The same is the case for <iframe>'s titles.