The Mozilla Platform contains more object facilities than can possibly be covered here. Because of its portability requirements, and because of its application focus, those objects tend to be high-level ones. Perhaps one day there will be a full POSIX interface, but the high-level application focus of the platform reduces the urgency of any such need.
Mozilla's XML processing facilities are particularly strong, which is no surprise. Heavyweight XML-based networks tend to be business-to-business rather than consumer-to-business, but Microsoft's .NET initiative suggests that there is plenty of need for sophisticated XML-based client-oriented software.
Having explored first the front half and now the back half of Mozilla-based applications, ...