OwnedBy is a read-only TPersistent property that identifies the persistent object that acts as the owner of the command handler instances in the collection. 

OwnedBy has been introduced in Indy to provide compatibility between VCL versions where Owner was not exposed in the TOwnedCollection ancestor class, and Delphi 6. In Delphi 6, OwnedBy prevents any conflict with the Owner property in TOwnedCollection that is used for memory management, assignment, and streaming. 

OwnedBy provides a read access specifier that ensures the OwnedBy property is returned as a TPersistent value. This avoids internal errors and potential crashes that may occur in Delphi 5.