.BOM File Extension

"Bill of Materials" (BOM) file created by the Mac OS X Installer; used to determine which files to install, update, or remove during a software update; contains files that have been installed and information about each file; may include Unix permissions, owner and group data, file size, last modified date, and a checksum for each file.

When BOM files are created, they are saved by default in the /Library/Receipts/boms folder. These files are referenced by the Mac OS X Installer and are not meant to be opened by the user.