On the one hand, a lot of those are feature requests, not necessarily bugs. They also have more users, so they catch more edge case bugs like "Hebrew is rendered backwards" and so on.
On the other hand, PDF.js has been around for more than a decade. As it is a core component of Firefox, and viewing PDFs is an important part of name business applications, you'd think they'd have not nearly so many issues.
I know PostScript and PDFs are a nightmare, but no small part of me feels like this is yet another case of Mozilla underfunding development.
In any case, there are more native speakers of right-to-left languages then there are native English speakers.
I found this and dropped their table into a sheet to get a a total of just over 2.3 billion. Languages using right-to-left scripts https://share.google/lN5lmfjCoIW7ENvdZ
When you're not a Hebrew speaker and you don't interact with Hebrew script, and you're developing a PDF library by yourself, it's easy to not even realize that there is something about it that you've overlooked.
In any case, Hebrew is handled differently from other RTL languages, hence this bug report in PDF.js: https://github.com/mozilla/pdf.js/issues/20097
Almost certainly something a smaller team would have never caught, given that a team with a massive name behind them didn't.
I don’t see dotancohene say anything about how surprising it is that that bug exists. They only say something about the judgment of it being an edge case.
I don't think there's an indication that this affects all RTL languages, just Hebrew word order in selections.
Specifically a right edge case
Nice!