The installer sets the Last Saved By summary information property to the value of the LogonUser property during an administrative installation. The installer never uses this property and a user never needs to modify it. Developers of a database editing tool may use this property to track the last person to modify the database. This property should be left set to null in a final shipping database.
In a transform, this summary property contains the platform and language ID(s) that a database should have after it has been transformed. The property specifies to what the Template should be set in the new database.
Win32 MSI APIs: MsiSummaryInfoGetProperty, MsiSummaryInfoSetProperty