What and how does this component work?

When calling the SendNotification action, it sends a Human Activity.

On the Application side when using the AsynchronousNotification Web Block, the Taskbox is hidden and a javascript logic is added to detect when there is a new human activity and trigger the Web Block's OnNotify event.

From there you can implement your own logic, for example

•  Updating a list of records.
• Give feedback to the user that a timer has failed or ended.
• Giving feedback that the process has been completed.

Note: It is necessary to activate the TaskBox for your module 

http://<server url>/EPA_Taskbox/ 

For more details, see this link

https://success.outsystems.com/Documentation/How-to_Guides/Processes/How_to_configure_EPA_taskbox_preferences