The System utility app provides triggers for when apps, actions, and triggers are added to the system:
The no-op trigger is a stub that always fires and emits no data.
The test data trigger will always emit its entered test data. It can be used for testing automations, or for mocking up automations when the actual input trigger data is not available.
The System actions can be used to interact and control automations, plus to obtain information about them:
Mouse over actions in the list to learn about their functionality: