diff --git a/.github/workflows/pr-build.yml b/.github/workflows/pr-build.yml
index 06098528..d4abcf2d 100644
--- a/.github/workflows/pr-build.yml
+++ b/.github/workflows/pr-build.yml
@@ -85,8 +85,10 @@ jobs:
           npm run build -- --mode preview --base "$base"
 
           # Recorded so the publish job can refuse a build made for the wrong
-          # path, instead of publishing a page that loads nothing.
-          printf '%s' "$base" > dist/.preview-base
+          # path, instead of publishing a page that loads nothing. Not a
+          # dotfile: actions/upload-artifact leaves hidden files out of the
+          # artifact by default, and this has to survive the trip.
+          printf '%s' "$base" > dist/preview-base
 
           # A CNAME means something only at the site root, and the root belongs
           # to the production deploy.
diff --git a/.github/workflows/pr-deploy.yml b/.github/workflows/pr-deploy.yml
index f25c7d77..70a7cd96 100644
--- a/.github/workflows/pr-deploy.yml
+++ b/.github/workflows/pr-deploy.yml
@@ -178,13 +178,13 @@ jobs:
           # blank, which is worth an error rather than a puzzled contributor.
           # Stripped of anything but path characters before being echoed, since
           # the file came from the build.
-          built_base="$(tr -dc 'A-Za-z0-9/._-' < preview/.preview-base 2>/dev/null || true)"
+          built_base="$(tr -dc 'A-Za-z0-9/._-' < preview/preview-base 2>/dev/null || true)"
           if [ "$built_base" != "$EXPECTED_BASE" ]; then
             echo "::error::this build is for '${built_base:-<unset>}' but the site serves '${EXPECTED_BASE}'."
             echo "::error::set PREVIEW_PUBLIC_BASE=${{ needs.resolve.outputs.base_path }} in frontend/.env.preview"
             exit 1
           fi
-          rm -f preview/.preview-base
+          rm -f preview/preview-base
 
       - name: Publish to gh-pages
         env: