iOS jailbreaking is the use of a kernel and/or userland exploit to remove software restrictions imposed by Apple on devices running iOS and iOS-based operating systems.
While legacy jailbreaks modified the system partition, modern 'rootless' jailbreaks (iOS 15+) work around the Sealed System Volume (SSV) to grant root access (UID 0) and sandbox escapes without modifying the read-only root filesystem. This allows for the installation of software and tweaks unavailable through the App Store by localizing them within a writable directory named /private/preboot/$boot-manifest-hash$/procursus, accessed through the /var/jb symlink for quick accessibility.
A jailbroken device typically permits root access within the operating system and provides the right to install software unavailable through the App Store. Different devices and versions are exploited with modern tools like Dopamine or palera1n. Apple views jailbreaking as a violation of the end-user license agreement and strongly cautions device owners not to try to achieve root access through the exploitation of vulnerabilities.
While sometimes compared to rooting an Android device, jailbreaking bypasses several types of Apple prohibitions for the end-user. Since it includes modifying the operating system (enforced by a "locked bootloader"), installing non-officially approved (not available on the App Store) applications via sideloading, and granting the user elevated administration-level privileges (rooting), the concepts of iOS jailbreaking are therefore technically different from Android device rooting.
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