Linux installer contains '.' directory in the tar.gz file

The Linux installer is packaged in a weird way: the root of the tar.gz file contains a single directory '.' (a single dot) with a directory 'linux.gtk.x86' in it. The latter directory then actually contains all the files. Why not have everything in a single directory like 'hippo-demo-3.04.00' instead? This looks much more professional to developers.