Bill of materials file
BOM is a file extension for a binary file created by the Mac OS X installer. BOM stands for Bill Of Materials. BOM files contain information used to determine which files to install, update, or remove during a software update; contains files that have been installed; may include Unix permissions, owner and group data, file size, last modified date, and a checksum for each file. BOM files are referred to by the Mac OS X installer, and not intended to be directly opened.
Learn more about .BOM files:
Visit the Apple web page.
Read about Mac OS X at ITKnowledgeExchange.com.