BUNDLE - Mac OS X Application Bundle
This is a file or plug-in that adds features to the Mac OS X operating system or to update Mac applications. They may provide driver support for audio and video cards, printer drivers, Dreamweaver extensions as well as additional effects for iMovie. These files are generally found in the /System/Library subdirectory while others may be stored in the specific applications or applications support directories. These files are used only by the installation and support programs within Mac OS X and should not be opened with other programs.