A web tool that converts PDF scientific papers into HTML | Boing Boing
https://boingboing.net/2021/09/17/a-web-tool-that-converts-pdf-scientific-papers-into-html.html

There's a bunch of Linux command line tools that do converting, but they often mess up on things like tables and embedded images.  Libreoffice could do a fair job sometimes.  Having a web option is nice, especially for phones and mobile.