The content-type for the gzip files we make available for download is application/x-gzip. This causes problems with some browsers that don't understand this content type.
According to RFC6648 the x- types are deprecated, and RFC6713 says the right type for gzip files is application/gzip.
The work in this ticket has two parts:
- Update evergreen.yml to use the right content type for new files
- Update the existing files to have the right content type