The common idea is to limit the Firefox browser to functions for kiosk style browsing. Limit most Firefox features to convey simplicity, familiarity and principle of least astonishment.
Used in "Enterprise" deployments, schools, libraries, signs, shops and banks!
http://webconverger.org/kiosk/ shows how it is used in the Webconverger Linux distribution.
Found a way to circumvent the extension? Please let us know!
Many thanks to security researcher and "kiosk hacker" Paul Craig for his contributions.