https://www.siliconvalley.com/2023/09/19/the-iphones-new-action-button-is-more-than-a-one-trick-pony/

But one new feature easily stands out: The Action Button.

Apple has repurposed its physical mute button on the side of its high-end models into a more customizable tool, allowing users to carry out a handful of commands, from recording a voice memo and taking a picture to turning on the flashlight. The button can also be programmed to launch any app or shortcut, essentially turning it into a remote control or launching pad to gain quick access to something you want on demand.