[[!comment format=mdwn
 username="joey"
 subject="""comment 1"""
 date="2017-08-15T17:28:20Z"
 content="""
The normal reason for this to happen is if the size of the file
on the website has changed. git-annex checks the reported size and if it
differs from the versioned file, it knows that the website no longer
contains the same file.

In this case, it seems to be a cgi program generating a zip file, and the
program actually generated two different zip files when I hit it twice with
wget. (So if git-annex actually did drop the only copy of the version you
downloaded, you'd not be able to download it again. Not that git-annex can know
that; this kind of thing is why trusting the web is not a good idea..) They did
have the same size, but it looks like the web server is not sending a size
header anyway.

The actual problem is the web server takes a long time to answer a HEAD request
for this URL. It takes 35 seconds before curl is able to HEAD it. I suspect
it's generating the 300 mb zip file before it gets around to finishing
the HEAD request. Not the greatest server behavior, all around.

That breaks http-client due to its default 30 second timeout. So, will remove that timeout then.
"""]]