/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated softwareupdated is the main daemon responsible for running software updates.
The binary is a part of softwareupdated application.
/System/Library/PrivateFrameworks/MobileSoftwareUpdate.framework/Support/softwareupdated softwareupdated is the main daemon responsible for running software updates.
The binary is a part of MobileSoftwareUpdate private framework.