content, rather than a custom system. Help Viewer's implementation in Mac OS X 10.5 (Leopard) found its way to Rob Griffiths' list of Leopard criticisms, because Apple changed the software from a standalone application with a standard window interface to one with a floating window that always appears in front of all other application windows, obscuring the interface for which one is seeking help (see image below). Although one can close or minimize the Help Viewer window, it is difficult to consult the Help Viewer while simultaneously working with the application, short of changing the size of windows so both fit on the screen. The Help Viewer window also does not work with the Exposé window management feature (Mission Control in OS X 10.7 or later). There is a workaround using the defaults command accessible in the Terminal. iOS App Installer iOS App Installer is an app that downloads .ipa files for iPadOS applications so that they can be run on Apple silicon-based Macs. Installer Installer extracts and installs files out of .pkg packages, allowing developers to create uniform software installers. Installer launches when a package or metapackage file is opened. The installation process itself can vary substantially, as Installer allows developers to customize the information the user is presented with. For example, it can be made to display a custom welcome message, software license and readme. Installer also handles authentication, checks that packages are valid before installing them, and allows developers to run custom scripts at several points during the installation process. Installer packages have the file extension . Prior to Mac OS X Leopard, installer packages were implemented as Mac OS X packages. These packages were a collection of files that resided in folders with a .pkg file extension. In Mac OS X Leopard the software packaging method was changed to use the XAR (eXtensible ARchiver) file format; the directory tree containing the files is packaged as an xar archive file with a extension. Instead of distributing multiple files for a package, this allowed all of the software files to be contained in a single file for easier distribution with the benefit of package signing. loginwindow The loginwindow process displays the macOS login window at system startup if auto-login is not set, verifies login attempts, and launches login applications. It also implements the Force Quit window, restarts macOS user interface components (the Dock and Finder) if they crash,