MIME types & the Application Registry
MIME types provide a standardized for denoting the content of files or
file streams. GnomeVFS exposes simple methods for both identifying the
MIME type of a particular file, and deciding how to act on it. The MIME
and application registries provide a mapping between files of a particular
mime type and applications / bonobo components which can view or edit
those files. Applications such as Nautilus use this database to generate
appropriate actions when files are activated.