User interface > Translation options > Type options > Interface GUD's
At the Type Options page, you can view the table of GUIDs already assigned to interfaces and define new assignments. This applies to interfaces that do not have an explicit GUID in the original Delphi code.
Delphi2Cpp automatically generates new GUIDs for such interfaces. To avoid different GUIDs being generated on each translation, previously generated values can be restored here and reused in future translations.
If the GUID field is left empty, no GUID will be assigned to the interface.