Comment by Per_Bothner

The libwebsockets server (https://libwebsockets.org) supports serving directly from zip archives. Furthermore, if a URL is mapped to a compressed archive member, and assuming the browser can accept gzip-compressed files (as most can), then the compressed data is copied from archive over http to the browser, without de-compressing or conversion by the server. The server does a little bit of header fiddling but otherwise sends the raw bytes to the browser, which automatically decompresses it.