Can you explain what is meant by 'cold signal' in your context?.

In the context of iOS, the term "cold signal" usually refers to signals or events that come from external sources and are not directly related to the current state of the application or user interaction. For example, these could be push notifications that arrive when the app is inactive or not running.

Another meaning is a signal that launches the app "from scratch," meaning when the app was not running in the background and receives an event that causes it to wake up and handle this signal.

Thus, a "cold signal" is an event that initiates the app's operation from a state of rest, unlike "hot" signals, which occur during active app operation.