The feature in question relates to a visual theme offered within the Gmail application on Apple’s mobile operating system. It inverts the color scheme, presenting light text on a dark background. This is a setting available to users of the Gmail application on iPhones and iPads.
Adopting a darker interface can reduce eye strain, particularly in low-light conditions. It may also contribute to conserving battery power on devices with OLED screens. Furthermore, some users find the altered aesthetics more visually appealing. Historically, dark themes have become increasingly popular across various software platforms due to these perceived advantages.