Filesystem:/Applications

Summary
This is where all of the pre-installed native apps, as well as native jailbreak apps (from Cydia and elsewhere), are installed. They can't be deleted under normal circumstances. One can delete them on a jailbroken device through some sort of file-management tool such as SSH or iFile, although doing this is highly unrecommended as they can't be re-installed.

New user apps are installed via iTunes or the App Store in the Filesystem:/private/var/mobile/Applications folder.

Apple TV
The versions referred to here correspond to the displayed/marketing version, not the internal version.

Unofficial Apps
These application bundles are not present on an unmodified system and are generally installed via a PC utility, manually or through a package. More applications may be installed after jailbreak.
 * Installer.app (AppTapp Installer)
 * blackra1n.app (blackra1n and limera1n)
 * Cydia.app (Cydia Installer)

Files
(none)