The private unicode range is often used for icons on many web sites, but downloadable fonts are considered optional on the web, so we're left with unintelligibl

The private unicode range is often used for icons on many web sites, but downloadable fonts are considered optional on the web, so we're left with unintelligible hex codes instead, at which point we've regressed to a pre-accessibility era when images typically didn't come with alt text, but at least there was a fallback mechanism.