Restore comment

.github/workflows/ci.yml

@@ -204,10 +204,14 @@ jobs:
       fail-fast: false
       matrix:
         include:
+            # macos-15 is arm64[0] which doesn't support nested
+            # virtualization[1].
+            #
+            # [0] https://github.com/actions/runner-images#available-images
+            #
+            # [1] https://docs.github.com/en/actions/reference/runners/github-hosted-runners#limitations-for-arm64-macos-runners
           - target: x86_64-apple-darwin
             os: macos-15-intel
-          - target: aarch64-apple-darwin
-            os: macos-15
 
           # We don't use ubuntu-latest because we care about the apt packages available.
           - target: x86_64-unknown-linux-gnu