diff --git a/tools/vendor_datasets.py b/tools/vendor_datasets.py
index 5b0f25fe8..08c3094e7 100644
--- a/tools/vendor_datasets.py
+++ b/tools/vendor_datasets.py
@@ -1,3 +1,10 @@
+"""
+Adapted from `altair-viz/vega_datasets`_.
+
+.. _altair-viz/vega_datasets:
+    https://github.com/altair-viz/vega_datasets
+"""
+
 from __future__ import annotations
 
 import sys