diff --git a/.github/workflows/check-xml.yml b/.github/workflows/check-xml.yml
index 550ea31c3..0c83ae246 100644
--- a/.github/workflows/check-xml.yml
+++ b/.github/workflows/check-xml.yml
@@ -19,9 +19,16 @@ jobs:
     name: "Check XML"
     runs-on: ubuntu-22.04
     steps:
+      # The translation at the root, doc-en under en/: this is the layout
+      # check-structure.php expects. The explicit ref takes the real head of
+      # the pull request, not the merge commit actions/checkout builds by
+      # default: that one has master as its second parent, so the diff below
+      # would also list every file landed on master since the last push.
+
       - name: "Checkout translation"
         uses: actions/checkout@v7
         with:
+          ref: ${{ github.event.pull_request.head.sha }}
           fetch-depth: 0
 
       - name: "Checkout php/doc-en"