You can clone with
HTTPS or Subversion.
This would be useful for static file servers, so that browsers could use their caching algorithms. With a programmatic access this would also be useful in thefiletree, so that browsers (and android apps for that matter) can also cache files there.
This is the technique used in #22 to leverage browser caching. Reminder:
ask.res.setHeader('Last-Modified', new Date().toGMTString());