There is no publicly known information about an "iOS 26 beta 3". Apple's current operating system is iOS 17, and it's highly unlikely they would jump to iOS 26. Typically, Apple releases yearly updates, with iOS 18 expected sometime in 2024. Information about any future iOS versions beyond the currently released ones is usually kept tightly under wraps until official announcements. Therefore, any information you might find online about "iOS 26 beta 3" should be treated with extreme skepticism.