Purpose - Everything related to the concept of Task, Job or Request.

The TaskManagement is an infrastructure or low-level subsystem. See Section 4.4, “Low-level subsystems”. Currently, this subsystem contains the ProgressMonitor.

The ProgressMonitor is explained by the following: SomethingA needs a long running service from SomethingB. So, SomethingA decides to ask for it in a different Thread of execution and to monitor the progress of the task in its main thread. The reason why it monitors the progress could be because it wants to show feedback to the user via the GUI, but, it could also be in order to decide that if there is no progress, it should give up by interrupting its other Thread.