The first web browser was also an editor (albeit not for PDFs). Accessible editing was a part of was Berners-Lee's vision for the web.
> The first web browser - or browser-editor rather - was called WorldWideWeb as, after all, when it was written in 1990 it was the only way to see the web.[1]
> The first web browser - or browser-editor rather - was called WorldWideWeb as, after all, when it was written in 1990 it was the only way to see the web.[1]
[1] https://www.w3.org/People/Berners-Lee/WorldWideWeb.html