"RCDefaultApp is a Mac OS X 10.2 or higher preference pane that
allows a user to set the default application used for various URL
schemes, file extensions, file types, MIME types, and Uniform Type
Identifiers (or UTIs; MacOS 10.4 only). MacOS X uses the extension and
file type settings to choose the application when opening a file in
Finder, while Safari and other applications use the URL and MIME type
settings at other times for content not related to a file (such as an
unknown URL protocol, or a media stream).
RCDefaultApp
also allows setting the application when digital cameras or FireWire
webcams such as iSight are connected to the computer. For completeness'
sake, there are also settings that mimic the existing "CDs and DVDs"
preference pane, which allows setting the action to take when various
types of CDs and DVDs are inserted into the computer."