I just work from the HTML specs and go my own way. There is something I am working on that 'needs' this stuff. I see HTML as a creative medium and I wanted to solve problems such as internal document navigation - rather than hundreds of web pages, compile the lot into one.

The PWA takes an entirely different approach to what I am trying to do. I like the PWA approach but I want one file that can be moved or emailed, to be available offline.

I found that making all the images inline worked for me. I got best results with webp rather than avif but don't care about losing the size benefits with base64 encoding - once zipped those compress nicely.