diff --git a/openeo_driver/ProcessGraphDeserializer.py b/openeo_driver/ProcessGraphDeserializer.py
index 8eaee1a9..2bfc3bec 100644
--- a/openeo_driver/ProcessGraphDeserializer.py
+++ b/openeo_driver/ProcessGraphDeserializer.py
@@ -1322,7 +1322,9 @@ def run_udf(args: dict, env: EvalEnv):
     if isinstance(data, AggregatePolygonResult):
         pass
     if isinstance(data, DriverVectorCube):
-        # TODO: this is temporary adaption to old style save results. Better have proper DriverVectorCube support in run_udf?
+        # TODO: this is temporary stopgap measure, converting to old-style save results to stay backward compatible.
+        #       Better have proper DriverVectorCube support in run_udf?
+        #       How does that fit in UdfData and UDF function signatures?
         data = data.to_legacy_save_result()
 
     if isinstance(data, (DelayedVector, dict)):
diff --git a/openeo_driver/dummy/dummy_backend.py b/openeo_driver/dummy/dummy_backend.py
index 8adf0ba4..c3d6e791 100644
--- a/openeo_driver/dummy/dummy_backend.py
+++ b/openeo_driver/dummy/dummy_backend.py
@@ -228,6 +228,7 @@ def assert_polygon_sequence(geometries: Union[Sequence, BaseMultipartGeometry])
                 coords[self.metadata.band_dimension.name] = self.metadata.band_names
             shape = [len(coords[d]) for d in dims]
             data = numpy.arange(numpy.prod(shape), dtype="float")
+            # Start with some more interesting values (e.g. to test NaN/null/None handling)
             data[0] = 2.345
             data[1] = float("nan")
             cube = xarray.DataArray(