deactivated ProofContext.transfer_used_names; eliminated PureThy.default_name ("" not stored);
deactivated ProofContext.transfer_used_names;
eliminated PureThy.default_name ("" not stored);

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle