diff --git a/src/server/package/src/model_explorer/graph_builder.py b/src/server/package/src/model_explorer/graph_builder.py
index bf3f8590..01d1ea8b 100644
--- a/src/server/package/src/model_explorer/graph_builder.py
+++ b/src/server/package/src/model_explorer/graph_builder.py
@@ -189,6 +189,10 @@ class GraphNodeConfig:
   pinToGroupTop: bool = False
 
 
+# From group's namespace to its attribuets (key-value pairs).
+#
+# Use empty group namespace for the graph-level attributes (i.e. shown in
+# side panel when no node is selected).
 GroupNodeAttributes = Dict[str, Dict[str, str]]