Here's how the dedicated physical button called Essential Key will work on Nothing Phone (3a) series

Nothing will unveil the Nothing Phone (3a) and Nothing Phone (3a) Pro on March 4, and both phones will feature a dedicated camera button. Nothing previously revealed they considered adding a red dot to this button, and we now know how it will work.

The source claims that this button will be called Essential Key, and that's because it will be used to invoke Nothing's custom AI, which will be baked into an app called Essential Space. It will be an "AI-powered hub" to store digital content like screenshots, voice notes, and photos.

You can press and hold the Essential Key to capture a screenshot, while a long-press will record a voice note and a double-tap will let you quickly access the content stored in Essential Space. Inside the phone's native Camera app, you can single-press the Essential Key to click a photo.

The source claims that Essential Space is a work in progress, but it will still debut on the Nothing Phone (3a) and Phone (3a) Pro. A full-fledged version will likely arrive with the Nothing Phone (3) later.

Source