[[!comment format=mdwn
 username="joey"
 subject="""comment 6"""
 date="2017-07-12T18:09:00Z"
 content="""
That would almost work without any smarts on the git-annex side.
When it tells the special remote to `REMOVEEXPORT`, the special remote
could remove the file from the HEAD equivilant but retain the content in its
versioned snapshots, and keep the url to that registered. But, that
doesn't actually work, because the url is registered for that special
remote, not the web special remote. Once git-annex thinks the file has been
removed from the special remote, it will never try to use the url
registered for that special remote.

So, to support versioning-capable special remotes, there would need to be
an additional response to `REMOVEEXPORT` that says "I removed it from HEAD,
but I still have a copy in this url, which can be accessed using
the web special remote".
"""]]