private static DataFlavor createLocalDataTypeFlavor() {

		try {
			return new GenericDataFlavor(DataFlavor.javaJVMLocalObjectMimeType +
				"; class=java.util.ArrayList", "Local code unit info object");
		}
		catch (Exception e) {
			Msg.showError(CodeUnitInfoTransferable.class, null, "Could Not Create Data Flavor",
				"Unexpected exception creating data flavor for code unit info", e);
		}

		return null;
	}
DataFlavor that it is an ArrayList of CodeUnitInfo objects.
Ghidra/Features/Base/src/main/java/ghidra/app/util/CodeUnitInfoTransferable.java