iOS - Wikipedia
https://en.wikipedia.org/wiki/IOS
iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that powers many of the company's mobile devices, including the iPhone and iPod Touch...
Download iOS Firmware for iPhone, iPad, iPod... / IPSW Downloads
https://ipsw.me/
Download current and previous versions of Apple's iOS, iPadOS, watchOS, tvOS and audioOS firmware and receive notifications when new firmwares are released.
iOS | Apple Wiki | Fandom
https://apple.fandom.com/wiki/IOS
iOS (formerly iPhone OS) is a mobile operating system from Apple Inc. Originally developed for the iPhone, it has since been extended to support other Apple devices including the original Apple TV, iPod touch and iPad.