diff --git a/tests/ref/basic.list b/tests/ref/basic.list
index 622aacc0fe1..62500b43965 100644
--- a/tests/ref/basic.list
+++ b/tests/ref/basic.list
@@ -344,7 +344,6 @@ resolution=300x300,device-pixel-ratio=2 != pixel_snapping_position_a.html pixel_
== text_transform_none_a.html text_transform_none_ref.html
== text_transform_uppercase_a.html text_transform_uppercase_ref.html
== transform_3d.html transform_3d_ref.html
-== transform_optimization.html transform_optimization_ref.html
flaky_cpu,prefs:"layout.writing-mode.enabled" == vertical-lr-blocks.html vertical-lr-blocks_ref.html
== viewport_meta.html viewport_rule_ref.html
resolution=800x600 == viewport_percentage_vmin_vmax.html viewport_percentage_vmin_vmax_a.html
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index b18d144c6b4..f64a9c710ed 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -603,6 +603,18 @@
"url": "/_mozilla/css/stacking_context_rtl.html"
}
],
+ "css/transform_optimization.html": [
+ {
+ "path": "css/transform_optimization.html",
+ "references": [
+ [
+ "/_mozilla/css/transform_optimization_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/transform_optimization.html"
+ }
+ ],
"css/transform_simple_a.html": [
{
"path": "css/transform_simple_a.html",
@@ -2144,6 +2156,18 @@
"url": "/_mozilla/css/stacking_context_rtl.html"
}
],
+ "css/transform_optimization.html": [
+ {
+ "path": "css/transform_optimization.html",
+ "references": [
+ [
+ "/_mozilla/css/transform_optimization_ref.html",
+ "=="
+ ]
+ ],
+ "url": "/_mozilla/css/transform_optimization.html"
+ }
+ ],
"css/transform_simple_a.html": [
{
"path": "css/transform_simple_a.html",
diff --git a/tests/ref/transform_optimization.html b/tests/wpt/mozilla/tests/css/transform_optimization.html
similarity index 88%
rename from tests/ref/transform_optimization.html
rename to tests/wpt/mozilla/tests/css/transform_optimization.html
index db2c1ad4181..9811511e1f8 100644
--- a/tests/ref/transform_optimization.html
+++ b/tests/wpt/mozilla/tests/css/transform_optimization.html
@@ -1,6 +1,7 @@
+