> Another spiritually similar idea being championed at the time came from the Opera browser folks who wanted to put "a web server in your browser".

Opera Unite was such an awesome idea. https://arstechnica.com/information-technology/2009/06/opera...

There was a neat idea a bit back to allow Service Workers to work across origin: foreign fetch. It wasn't on the internet, was only in the scope of your browser, but I thought it was such a neat advancement. Would have done so much to allow the offline web to weave itself. Alas, deprecated. https://developer.chrome.com/blog/foreign-fetch