Dracut now has a wiki page in the Fedora wiki...

[Bruno Wolff III]

On Fri, Jul 03, 2009 at 10:43:34 +0100,
  Adam Williamson <awilliam at redhat.com> wrote:
> 
> but it's actually a lot less trouble to just do:
> 
> "tar xf dracut-$version.tar.bz2"
> 
> which auto-detects the archive type. It's much easier to just let it be
> handled by autodetection, and only bother specifying the archive type
> manually if the autodetection trips up.

How long has that feature been there?