What are "Aliases" under Open Directory's local node?

If I run dscl . -readall Aliases I get the following: dsAttrTypeNative:members: root AppleMetaNodeLocation: /Local/Default RecordName: administrator RecordType: dsRecTypeStandard:Aliases - dsAttrTypeNative:members: root AppleMetaNodeLocation: /Local/Default RecordName: dumper RecordType: dsRecTypeStandard:Aliases - dsAttrTypeNative:members: postmaster AppleMetaNodeLocation: /Local/Default RecordName: MAILER-AGENT RecordType: dsRecTypeStandard:Aliases - dsAttrTypeNative:members: postmaster AppleMetaNodeLocation: /Local/Default RecordName: MAILER-DAEMON RecordType: dsRecTypeStandard:Aliases - dsAttrTypeNative:members: root AppleMetaNodeLocation: /Local/Default RecordName: manager RecordType: dsRecTypeStandard:Aliases - dsAttrTypeNative:members: root AppleMetaNodeLocation: /Local/Default RecordName: nobody RecordType: dsRecTypeStandard:Aliases - dsAttrTypeNative:members: root AppleMetaNodeLocation: /Local/Default RecordName: operator RecordType: dsRecTypeStandard:Aliases - dsAttrTypeNative:members: root AppleMetaNodeLocation: /Local/Default RecordName: postmaster RecordType: dsRecTypeStandard:Aliases When are these aliases used? In particular, I'm worried that a nobody user (which is also a real user) is aliased to root.