A module is an application that implements the Module interface, whose lifecycle is tightly bound to the story in which it was started and may implement a UI. A module is started in a story by another module or by the system from which it receives a Link service . It can also receive / provide other services via ServiceProviders. A module is terminated if the story in which it is running becomes inactive, or the module that started it decides to terminate it or it decides to terminate itself. A module can start other modules, create, send / receive messages and call FIDL interfaces.