This is a signed default.xbe which is a shortcut to E:\Apps\xbmc\default.xbe, basically if you have a softmodded Xbox it's an easy way to boot directly in to XBMC. I used this on the Xbox's i softmodded for my friends many years ago and they never had any problems with it.
Note: be sure you have a working XBMC setup in E:\Apps\xbmc\ before replacing your default dashboard with this .xbe
Download: Xbox Signed Default XBE Download
Note: be sure you have a working XBMC setup in E:\Apps\xbmc\ before replacing your default dashboard with this .xbe
Download: Xbox Signed Default XBE Download