light - Windows Installer XML Linker
The Windows Installer XML linker is exposed by light.exe. light is responsible for processing one or more .wixobj files, retrieving metadata from various external files and creating a Windows Installer database (MSI or MSM). When necessary, light will also create cabinets and embed streams in the created Windows Installer database.
Light works through the mechanics of generating IDT files and importing them into the Windows Installer database. After the database is fully created, the final post processing is done to merge in any Merge Modules and create a cabinet if necessary.