Correct Content-Type header values for archive downloads. The content type for both .tar.gz and .tar.bz2 downloads was application/x-tar, which is correct for .tar files when no Content-Encoding is present, but is not correct for .tar.gz and .tar.bz2 files unless Content-Encoding is set to gzip or x-bzip2, respectively. However, setting Content-Encoding causes browsers to undo that encoding during download, when a .gz or .bz2 file is usually the desired artifact. Omitting the Content-Encoding header is preferred to avoid having browsers uncompress non-render-able files. Additionally, the Content-Disposition line indicates a final desired filename with .tar.gz or .tar.bz2 extension which makes providing a Content-Encoding header inappropriate. With the current configuration browsers (Chrome and Firefox thus far) are registering the application/x-tar Content-Type and not .tar extension and appending that extension, yielding filename.tar.gz.tar as a final on-disk artifact. This was originally reported here: http://stackoverflow.com/questions/3753659 I've changed the .tar.gz and .tar.bz2 Content-Type values to application/x-gzip and application/x-bzip2, respectively. Which yields correctly named download artifacts on Firefox, Chrome, and IE.