- Application Registry - 
stores supported MIME types and URIs of various applications
- File Types - 
functions for getting information about files based on their MIME type
- MIME Database Monitor - 
monitor the MIME database for changes (primarily for file browsers)
      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.