The browser natively supports several content types, such as text/html and the like. When a browser encounters content of a type it does not recognize, the unknown content type system is used to decide how a file of a particular type is to be handled.
- Protocol Handling - if loaded locally, looks up any registered handler locally and dispatches for the current shell, otherwise sends out to the OS
- UCT System - A system for handling content of unrecognized types
- Web Protocol Handler - A protocol handler that registers web based services as system (OS-level) handlers for given protocol schemes, e.g. mailto:, feed:, webcal: etc.
- Internal Handlers - depend on application. In UCT situations, these can include network error-like display pages that advertise other available options in a more human-readable format than the tiny UCT dialog does today.