diff --git a/pr-checks/checks/runner-images.yml b/pr-checks/checks/runner-images.yml
index 70354e9ad..a5042b0ba 100644
--- a/pr-checks/checks/runner-images.yml
+++ b/pr-checks/checks/runner-images.yml
@@ -1,7 +1,8 @@
 name: "Runner images"
 description: "An end-to-end integration test checking that CodeQL can analyze interpreted and compiled code on the GitHub-hosted runner images"
 # This check runs on each image listed in
-# https://github.com/actions/runner-images#available-images, except for:
+# https://github.com/actions/runner-images#available-images, except for images that GitHub has
+# retired or is about to retire, and:
 # - `ubuntu-slim`, which is intended for lightweight jobs rather than builds like this one.
 # - `windows-11-arm`, since CodeQL doesn't support Windows on Arm64.
 # - `xcode-27`, a preview image that the `unsupported-macos` check runs on.