Comment 1 for bug 440282

Looks like content-type of the served .xml file should be similar.

$ curl -v http://bookserver.archive.org/catalog/opensearch.xml
* About to connect() to bookserver.archive.org port 80 (#0)
* Trying 207.241.229.39... connected
* Connected to bookserver.archive.org (207.241.229.39) port 80 (#0)
> GET /catalog/opensearch.xml HTTP/1.1
> User-Agent: curl/7.16.4 (i486-pc-linux-gnu) libcurl/7.16.4 OpenSSL/0.9.8e zlib/1.2.3.3 libidn/1.0
> Host: bookserver.archive.org
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Fri, 02 Oct 2009 00:03:54 GMT
< Server: Apache/2.2.11 (Ubuntu) PHP/5.2.3-1ubuntu6 mod_ssl/2.2.11 OpenSSL/0.9.8e mod_wsgi/2.3 Python/2.5.1
< Vary: Accept-Encoding
< Transfer-Encoding: chunked
< Content-Type: application/atom+xml
<