This is a revision of https://gist.github.com/annevk/6174119 focusing on putting the semantics in the fragment identifier instead. The fragment identifier would follow http://www.w3.org/TR/media-frags/ (media-frags) and we'd introduce a new keyword http://www.w3.org/TR/media-frags/#processing-name-value-lists "path":
The general structure would be:
{URL-to-zip}#{media-frags}
http://fetch.spec.whatwg.org/ would be modified to support sub-responses for zip resources. First the resource would be fetched and then if it's a zip resource (signature sniffing) the fragment identifier would be processed per media-frags. The "path" keyword would be used to locate the sub-resource.