Archive Utility (BOMArchiveHelper until Mac OS X 10.5) is the default archive file handler in OS X. It is usually invoked automatically when opening a file in one of its supported formats. It can be used to create compressed ZIP archives by choosing "Create archive of 'file'" (Leopard: "Compress") in the Finder's File or contextual menu. It is located in /System/Library/CoreServices/Archive Utility.app in 10.5 and later, and /System/Library/CoreServices/BOMArchiveHelper.app in 10.4 Prior to Archive Utility's inclusion in Mac OS X v10.3, beginning with Mac OS 7.6, Apple bundled the freeware StuffIt Expander with the operating system.
Invoking Archive Utility manually shows a minimal GUI letting the user change Archive Utility preferences or choose files to compress or uncompress. BOMArchiveHelper 10.4.11 cannot be manually invoked. It may be inferred that prior to 10.5, BOMArchiveHelper could not be manually invoked.
BOM is an abbreviation of Bill of Materials. Bill of Materials files or .bom files are used by the OS X Installer program to document where files in an installer bundle are installed, what their file permissions should be, and other file metadata. Thus, a Bill of Materials is read by the Installer, and Archive Utility helps it by extracting the files specified in the BOM.