diff --git a/.github/labeler.yml b/.github/labeler.yml
index 43a1246ba68a..75adfed57f43 100644
--- a/.github/labeler.yml
+++ b/.github/labeler.yml
@@ -89,6 +89,7 @@
           - 'doc/conf.py'
           - 'doc/Makefile'
           - 'doc/make.bat'
+          - 'doc/sphinxext/**'
 "Documentation: devdocs":
   - changed-files:
       - any-glob-to-any-file:
diff --git a/doc/sphinxext/missing_references.py b/doc/sphinxext/missing_references.py
index 9c3b8256cd91..87432bc524b4 100644
--- a/doc/sphinxext/missing_references.py
+++ b/doc/sphinxext/missing_references.py
@@ -100,10 +100,11 @@ def handle_missing_reference(app, domain, node):
     #. record missing references for saving/comparing with ignored list.
     #. prevent Sphinx from raising a warning on ignored references.
     """
-    typ = node["reftype"]
+    refdomain = node["refdomain"]
+    reftype = node["reftype"]
     target = node["reftarget"]
     location = get_location(node, app)
-    domain_type = f"{domain.name}:{typ}"
+    domain_type = f"{refdomain}:{reftype}"
 
     app.env.missing_references_events[(domain_type, target)].add(location)