The iOS font, known as "San Francisco," was not actually discovered but rather developed by Apple specifically for their iOS operating system. Apple introduced the San Francisco font with the release of iOS 9 in 2015. Before San Francisco, Apple primarily used a font called "Helvetica Neue" as the system font for iOS. However, as Apple started introducing higher-resolution displays, they felt the need for a custom font that could optimize legibility and readability on their devices. Apple's design team worked on creating a font. The result was San Francisco, a modern sans-serif typeface designed with legibility in mind. It features subtle adjustments to letterforms, spacing, and proportions to enhance clarity and readability on Apple's devices. The font was initially introduced for the Apple Watch, where legibility on a small screen was of utmost importance. It was later extended to iOS devices, including iPhones and iPads, with the release of iOS 9. San Francisco has become the default system font for iOS since then.