Yes, but it's not guaranteed to be self-contained. I wouldn't want to open a random HTML file knowing that it could phone home, or that the content might break one day without me realizing. There's a practical and psychological aspect to sharing `steves_paper_2014.html` versus `steves_paper_2014.offlinesitebundle`. The latter feels safe and immutable.
What you want is an HTML tag or response header that restricts network access, which the browser can then enforce. Offline or a list of allowed domains, this would be great for security in general. Not so great for advertisers though.
Then you have to verify that the tag is there, right? But if it has another extension like .offlinebundle you can know thay browsers will not make any extra requests.
