(I haven't felt the need for such a warning since approximately 1998, when people stopped relying so much on third-party web hosting via FTP, and Content-Type fields were generally accurate. I recommend upgrading your web browser: direct links to a tar file no longer cause the entire window to be filled with line noise; and, if you try one of these newer graphical browsers, even if that happens for some reason it doesn't mess up your TTY state.)