I am a twenty-year veteran of the making of scholarly editions in digital form, as editor, toolmaker, teacher, commentator, theorist and publisher.
If you see a character looking like a p with a bar through the descender in the title of this post, and you see it here too ꝑ , then ... read on. And if you don't, then read on (and let me know!)
Thirty years ago, when myself, Tim Berners-Lee, Lou Burnard and the web were much younger, every "special character" was a challenge, and a potential triumph or failure. "Special" meant something beyond ASCI 127 (ah, the acronyms!). It meant anything non-English, in the most limited BREXIT sense. E-acute was used by people from across the Channel, and a few Canadians, and not to be used without Special Equipment (in those days, a Macintosh computer). Devanagari was a distant dream, and right-to-left writing