What is iOS URL scheme hijacking and how do Universal Links provide a more secure alternative?

• A.Universal Links require a live network connection to resolve each tap, since the device re-fetches the apple-app-site-association file from Apple's CDN on every invocation (offline handling is not supported at all); URL scheme hijacking is closed because the fetch happens before routing. The tradeoff is a link that fails on an aircraft.
• B.iOS prevents URL scheme conflicts at submission, because App Store review rejects a bundle declaring a scheme another published app already claims (the reservation is recorded against the team identifier); no two store apps share a scheme, so hijacking never arises outside a sideloaded build. Universal Links add domain verification on top of that reservation.
• C.URL scheme hijacking depends on install order, since the launch services daemon awards a contested scheme to the first claimant on the device (a later installer is refused the registration outright); installing the legitimate app first therefore forecloses the attack entirely. Universal Links matter only for the reverse ordering.