diff --git a/.github/renovate.json5 b/.github/renovate.json5
index f19ba1d..21bf880 100644
--- a/.github/renovate.json5
+++ b/.github/renovate.json5
@@ -43,5 +43,11 @@
       automerge: false,
       labels: ["dependencies", "major-update"],
     },
+    {
+      description: "lowest.yml pins the oldest supported Python on purpose",
+      matchFileNames: [".github/workflows/lowest.yml"],
+      matchDepNames: ["python"],
+      enabled: false,
+    },
   ],
 }
diff --git a/.github/workflows/lowest.yml b/.github/workflows/lowest.yml
index f2b204f..0466399 100644
--- a/.github/workflows/lowest.yml
+++ b/.github/workflows/lowest.yml
@@ -41,6 +41,8 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v7
       with:
+        # The oldest supported Python. Renovate leaves it alone (see
+        # .github/renovate.json5).
         python-version: "3.10"
 
     - name: Install uv