diff --git a/.github/workflows/presubmit.yml b/.github/workflows/presubmit.yml
index 011b6ef67..848a4842f 100644
--- a/.github/workflows/presubmit.yml
+++ b/.github/workflows/presubmit.yml
@@ -29,9 +29,9 @@ jobs:
   build:
     name: Build all specs
     runs-on: ubuntu-latest
-    # We now refer to the container by its SHA instead of the name, to prevent
-    # caching problems when updating the image.
-    # container: khronosgroup/docker-images:asciidoctor-spec
+    # Refer to the khronosgroup/docker-images:asciidoctor-spec container by
+    # its SHA instead of the name, to prevent caching problems when updating
+    # the image.
     container: khronosgroup/docker-images@sha256:bd30a83285a2ea062598f053b5bd8ebc843e16c639c0e4cd88ab4bbb4e63ead3
 
     steps:
@@ -40,6 +40,11 @@ jobs:
           fetch-depth: 0
           submodules: recursive
 
+      - name: Understand CI file / repo structure
+        run: |
+            /bin/pwd
+            ls -a . ..
+
       - name: Generate core specs (HTML and PDF)
         run: |
           python3 makeSpec -clean -spec core OUTDIR=out.core -j 5 api c env ext cxx4opencl