Bugzilla

As far as I can tell this table just contains a mapping chars having a unicode in both forms (i.e. horizontal or vertical).
For example \u301C (wave dash) isn't the harfbuzz table because it doesn't have a vertical counterpart in unicode (see https://en.wikipedia.org/wiki/Wave_dash).
As reported in https://github.com/mozilla/pdf.js/issues/18384, there are some other issues I'll try to address asap.
That said, the best thing to do is to embed the fonts in the pdf and use them correctly to have the right form for each glyph.
In the pdf specs it's said that it could have some rendering issues in case the fonts aren't embedded... we're in this case.

As far as I can tell this table just contains a mapping for the chars having a unicode in both forms (i.e. horizontal or vertical).
For example \u301C (wave dash) isn't the harfbuzz table because it doesn't have a vertical counterpart in unicode (see https://en.wikipedia.org/wiki/Wave_dash).
As reported in https://github.com/mozilla/pdf.js/issues/18384, there are some other issues I'll try to address asap.
That said, the best thing to do is to embed the fonts in the pdf and use them correctly to have the right form for each glyph.
In the pdf specs it's said that it could have some rendering issues in case the fonts aren't embedded... we're in this case.