title: Firefox fails to decompress gzip files
body: <p>I have .gz files stored on AWS s3. </p>
  
  <p>Using the s3 REST-API, I'm generating authenticated links that point to individual files. I'm also setting the content-header options such that browsers requesting these urls will decompress and download the gzipped files as attachments.</p>
  
  <p>The generated s3 url looks like so:</p>
  
  <pre><code>https://MY_BUCKET.s3.amazonaws.com/PATH_TO/file.ext.gz
    ?AWSAccessKeyId=MY_KEY
    &amp;Expires=DATE_TIME
    &amp;Signature=MY_SIGNATURE
    &amp;response-content-disposition=attachment%3B%20filename%3D%22file.ext%22
    &amp;response-content-encoding=gzip
    &amp;response-content-type=application%2Foctet-stream
    &amp;x-amz-security-token=MY_TOKEN
  </code></pre>
  
  <p>The links behave as expected in: (All on OSX) Chrome (42.0.2311), Safari (8.0.6), Opera (29.0), </p>
  
  <p>but NOT Firefox (38.0.1)</p>
  
  <p>Firefox downloads and renames the file correctly but fails to decompress the gzipped file.</p>
  
  <p>The response headers of a GET request to the authenticated urls look like so:</p>
  
  <pre><code>Accept-Ranges:bytes
  Content-Disposition:attachment; filename="file.ext"
  Content-Encoding:gzip
  Content-Length:928
  Content-Type:application/octet-stream
  Date:SOME_DATE_TIME
  ETag:"MY_ETAG"
  Last-Modified:SOME_OTHER_DATE_TIME
  Server:AmazonS3
  x-amz-expiration:expiry-date="ANOTHER_DATE_TIME"
  x-amz-id-2:MY_AMZ_ID
  x-amz-request-id:MY_AMZ_REQUEST_ID
  x-amz-server-side-encryption:AES256
  </code></pre>
  
  <p>Does Firefox look for different headers and/or header values to indicate decompression?</p>