THIS COULD BE THE IPHONE 17 PRO HORIZONTAL CAMERA BUMP, SAYS RELIABLE LEAKER

Summary from the TLDR Design newsletter

Reliable leaker "Digital Chat Station" suggests the iPhone 17 Pro will feature a horizontal camera bump with three lenses, resembling the Pixel 9 Pro's design. While lens details remain unknown, the iPhone 17 Air is expected to have a single camera. Apple may switch from titanium to aluminum for the Pro model.