diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 970a176834c..a4d4802c469 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -226,7 +226,6 @@ flaky_cpu == linebreak_simple_a.html linebreak_simple_b.html
# Should be == with expected failure. See #2797
!= overconstrained_block.html overconstrained_block_ref.html
== overflow_auto.html overflow_simple_b.html
-== overflow_auto_stacking_order_a.html overflow_auto_stacking_order_ref.html
# Should be ==?
!= overflow_position_abs_inside_normal_a.html overflow_position_abs_inside_normal_b.html
== overflow_scroll.html overflow_simple_b.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 79962148925..ffe083a7621 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -683,6 +683,18 @@
"url": "/_mozilla/css/flex_nochild.html"
}
],
+ "css/overflow_auto_stacking_order_a.html": [
+ {
+ "path": "css/overflow_auto_stacking_order_a.html",
+ "references": [
+ [
+ "/_mozilla/css/overflow_auto_stacking_order_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/overflow_auto_stacking_order_a.html"
+ }
+ ],
"css/overflow_position_abs_inline_block.html": [
{
"path": "css/overflow_position_abs_inline_block.html",
@@ -3396,6 +3408,18 @@
"url": "/_mozilla/css/flex_nochild.html"
}
],
+ "css/overflow_auto_stacking_order_a.html": [
+ {
+ "path": "css/overflow_auto_stacking_order_a.html",
+ "references": [
+ [
+ "/_mozilla/css/overflow_auto_stacking_order_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/overflow_auto_stacking_order_a.html"
+ }
+ ],
"css/overflow_position_abs_inline_block.html": [
{
"path": "css/overflow_position_abs_inline_block.html",
diff --git a/tests/ref/overflow_auto_stacking_order_a.html b/tests/wpt/mozilla/tests/css/overflow_auto_stacking_order_a.html
similarity index 80%
rename from tests/ref/overflow_auto_stacking_order_a.html
rename to tests/wpt/mozilla/tests/css/overflow_auto_stacking_order_a.html
index 1e958302c35..62b33966305 100644
--- a/tests/ref/overflow_auto_stacking_order_a.html
+++ b/tests/wpt/mozilla/tests/css/overflow_auto_stacking_order_a.html
@@ -1,4 +1,5 @@
+