AirPod secret powers: "go into your Control Center and add the Hearing toggle into your Control Center. Doing this will unlock the first three features that I want to bring up."
https://9to5mac.com/2023/02/10/these-are-the-top-features-that-make-airpods-worth-owning-video/
Background noises, use iPhone as a microphone, decibel readings.
