From site: "Flex 4, codenamed Gumbo, is now beginning active development. The product plan is not yet complete, but a few themes are under consideration"
From site: "Prana is an Inversion of Control (IoC) Container for ActionScript 3.0, and more specifically the Flex framework. It enables you to configure objects and components in a non-intrusive way by describing them in an external xml document and having them loaded at runtime."