[accessibility] zero-width cmsy* glyphs and PDF/A

[Karl Berry]

Hello people with an interest in TeX accessibility --

After reading Ulrike's article in the latest TUGboat
(https://tug.org/TUGboat/tb41-1/tb127fischer-accessible.pdf), Claudio
Beccari wrote to me about the zero-width \not and \mapstochar glyphs in
cmsy* (and derivatives) breaking PDF/A compliance.  He wrote a brief
note about it back in 2010:
https://tug.org/pracjourn/2010-1/beccari/

He provides a macro work-around there. He proposes changing the fonts to
give those characters a tiny width, instead of being truly zero, but I
see no chance of Don (or other font maintainers) agreeing to that.

I admit I am not sure if accessibility work generally uses cm* (or derived)
fonts at all, or just using OpenType/TrueType/Unicode-ish fonts, but I
thought it couldn't hurt to mention it. --best, karl