allow the user to set a breakpoint in task execution by defining a task ...

...to pause at

Given a list of ordered tasks as returned by --list-tasks, this new option allows the user to tell the playbook to stop and wait for input at any task by name.

  --pause-at-task=PAUSE_AT
                        pause the playbook with a task matching this name

The usecase is allowing a user to define a breakpoint within the aggregate run of complex nested tasks and then to debug the system or new ansible modules.