diff --git a/Apps/Playground/Android/BabylonNative/CMakeLists.txt b/Apps/Playground/Android/BabylonNative/CMakeLists.txt
index 4e6de5055..5e6dc1c96 100644
--- a/Apps/Playground/Android/BabylonNative/CMakeLists.txt
+++ b/Apps/Playground/Android/BabylonNative/CMakeLists.txt
@@ -25,6 +25,7 @@ target_link_libraries(BabylonNativeJNI
     PRIVATE EGL
     PRIVATE log
     PRIVATE -lz
+    PRIVATE AbortController
     PRIVATE AndroidExtensions
     PRIVATE AppRuntime
     PRIVATE Blob
diff --git a/Apps/Playground/CMakeLists.txt b/Apps/Playground/CMakeLists.txt
index 10dee1166..3a7ba2014 100644
--- a/Apps/Playground/CMakeLists.txt
+++ b/Apps/Playground/CMakeLists.txt
@@ -13,7 +13,12 @@ set(DEPENDENCIES
     "../Dependencies/recast.js")
 
 set(SCRIPTS
+    "Scripts/cube_texture_polyfill.js"
+    "Scripts/dom_polyfill.js"
+    "Scripts/es2019_transpile.js"
     "Scripts/experience.js"
+    "Scripts/fetch_polyfill.js"
+    "Scripts/file_polyfill.js"
     "Scripts/playground_runner.js"
     "Scripts/validation_native.js"
     "Scripts/config.json")
@@ -134,6 +139,7 @@ endif()
 target_include_directories(Playground PRIVATE ".")
 
 target_link_libraries(Playground
+    PRIVATE AbortController
     PRIVATE AppRuntime
     PRIVATE Blob
     PRIVATE bx
diff --git a/Apps/Playground/Scripts/config.json b/Apps/Playground/Scripts/config.json
index de5743481..dfeef3861 100644
--- a/Apps/Playground/Scripts/config.json
+++ b/Apps/Playground/Scripts/config.json
@@ -892,8 +892,6 @@
         {
             "title": "NMEGLTF",
             "playgroundId": "#WGZLGJ#10320",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "nmegltf.png"
         },
         {
@@ -1026,7 +1024,7 @@
             "playgroundId": "#QJ71C6#5",
             "referenceImage": "node-material1.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Disabled to land sync PR; newly-added test in cascade path of Win32 V8 D3D11 ACCESS_VIOLATION (-1073741819). Will be re-enabled in follow-up fix PR."
+            "reason": "GUI text labels render with red text on red background instead of green (BN GUI color regression affecting many GUI tests)."
         },
         {
             "title": "Node material 2",
@@ -1089,7 +1087,7 @@
             "playgroundId": "#UAIZCS#0",
             "referenceImage": "lodbillboardinstances.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Newly added test crashes Win32 V8 D3D11 with ACCESS_VIOLATION (-1073741819)."
+            "reason": "Instanced billboard foliage renders red instead of green (BN vertex/instance color routing regression)."
         },
         {
             "title": "Nested BBG",
@@ -1108,15 +1106,11 @@
         {
             "title": "Anisotropic",
             "playgroundId": "#MAXCNU#1",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "anisotropic.png"
         },
         {
             "title": "Clear Coat",
             "playgroundId": "#YACNQS#2",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "clearCoat.png"
         },
         {
@@ -1124,14 +1118,14 @@
             "playgroundId": "#BS60AB#0",
             "referenceImage": "TransformStackPanel.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Newly added test crashes Win32 V8 D3D11 with ACCESS_VIOLATION (-1073741819)."
+            "reason": "GUI Transform StackPanel buttons render orange/red instead of green (BN GUI color regression)."
         },
         {
             "title": "GUI StackPanel",
             "playgroundId": "#LLVZ90#0",
             "referenceImage": "StackPanel.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Newly added test crashes Win32 V8 D3D11 with ACCESS_VIOLATION (-1073741819)."
+            "reason": "GUI StackPanel buttons render orange/red instead of green (BN GUI color regression)."
         },
         {
             "title": "GUI Slate",
@@ -1162,7 +1156,7 @@
             "renderCount": 50,
             "referenceImage": "LineEdgesRenderer.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Newly added test crashes Win32 V8 D3D11 with ACCESS_VIOLATION (-1073741819)."
+            "reason": "LineEdgesRenderer emits extra red lines not present in reference (likely Vector3.Cross precision or duplicate-edge dedup gap)."
         },
         {
             "title": "Simulate pointer",
@@ -1184,7 +1178,7 @@
             "renderCount": 5,
             "referenceImage": "clipplanes.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Newly added test crashes Win32 V8 D3D11 with ACCESS_VIOLATION (-1073741819)."
+            "reason": "GUI slider handles render red instead of green (BN GUI color regression); skull also has minor edge anti-aliasing differences."
         },
         {
             "title": "ShadowOnlyMaterial",
@@ -1287,7 +1281,7 @@
             "playgroundId": "#SLV8LW#3",
             "renderCount": 20,
             "excludeFromAutomaticTesting": true,
-            "reason": "Framebuffer creation fails on Win32 V8",
+            "reason": "GUI label backgrounds render red instead of white (BN GUI color regression).",
             "referenceImage": "advancedShadows.png"
         },
         {
@@ -1295,7 +1289,7 @@
             "playgroundId": "#B48X7G#64",
             "renderCount": 20,
             "excludeFromAutomaticTesting": true,
-            "reason": "Framebuffer creation fails on Win32 V8",
+            "reason": "GUI label backgrounds render red instead of white (BN GUI color regression).",
             "referenceImage": "advancedShadows2.png"
         },
         {
@@ -1375,76 +1369,58 @@
             "title": "GLTF Serializer with Negative World Matrix (left handed, once)",
             "playgroundId": "#KX53VK#88",
             "replace": "//options//, useRightHandedSystem = false; iterations = 1;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerNegativeWorldMatrix.png"
         },
         {
             "title": "GLTF Serializer with Negative World Matrix (left handed, twice)",
             "playgroundId": "#KX53VK#88",
             "replace": "//options//, useRightHandedSystem = false; iterations = 2;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerNegativeWorldMatrix.png"
         },
         {
             "title": "GLTF Serializer with Negative World Matrix (right handed, once)",
             "playgroundId": "#KX53VK#88",
             "replace": "//options//, useRightHandedSystem = true; iterations = 1;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerNegativeWorldMatrix.png"
         },
         {
             "title": "GLTF Serializer with Negative World Matrix (right handed, twice)",
             "playgroundId": "#KX53VK#88",
             "replace": "//options//, useRightHandedSystem = true; iterations = 2;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerNegativeWorldMatrix.png"
         },
         {
             "title": "GLTF Serializer Shared Buffer Conversions",
             "playgroundId": "#KX53VK#85",
             "replace": "//options//, meshCount = 2;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerSharedBufferConversions.png"
         },
         {
             "title": "GLTF Serializer Skinning and Animation",
             "playgroundId": "#DMZBX1#1",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "gltfSerializerSkinningAndAnimation.png"
         },
         {
             "title": "GLTF Serializer Skinning and Animation (Right Handed)",
             "playgroundId": "#DMZBX1#2",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "gltfSerializerSkinningAndAnimation.png"
         },
         {
             "title": "GLTF Serializer Morph Target Animation",
             "playgroundId": "#84M2SR#107",
             "renderCount": 2,
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "gltfSerializerMorphTargetAnimation.png"
         },
         {
             "title": "GLTF Serializer Morph Target Animation Group",
             "playgroundId": "#T087A8#29",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "gltfSerializerMorphTargetAnimationGroup.png"
         },
         {
             "title": "GLTF Serializer KHR draco mesh compression",
             "playgroundId": "#F8BF8N#3",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Draco loader passes 'utf8' to TextDecoder which only accepts 'utf-8'",
             "referenceImage": "glTFSerializerKhrDracoMeshCompression.png"
         },
         {
@@ -1457,63 +1433,57 @@
         {
             "title": "GLTF Serializer KHR gpu instancing",
             "playgroundId": "#1Q2BWN#10",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "excludedGraphicsApis": ["OpenGL"],
+            "reason": "Pixel diff 3.4% on OpenGL backend (Linux JSC); passes on D3D11.",
             "referenceImage": "glTFSerializerKhrGpuInstancing.png"
         },
         {
             "title": "GLTF Serializer KHR punctual light, left-handed",
             "playgroundId": "#FLXW8B#27",
             "replace": "//options//, roundtrip = true; useRightHandedSystem = false;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerKHRPunctualLightLH.png"
         },
         {
             "title": "GLTF Serializer KHR punctual light, right-handed",
             "playgroundId": "#FLXW8B#27",
             "replace": "//options//, roundtrip = true; useRightHandedSystem = true;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerKHRPunctualLightRH.png"
         },
         {
             "title": "GLTF Serializer Camera, left-handed",
             "playgroundId": "#O0M0J9#25",
+            "excludedGraphicsApis": ["OpenGL"],
+            "reason": "Camera roundtrip diverges on OpenGL backend (Linux JSC), 21% pixel diff; passes on D3D11.",
             "replace": "//options//, roundtripCount = 1; useRightHandedSystem = false;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerCameraLeftHand.png"
         },
         {
             "title": "GLTF Serializer Camera, right-handed",
             "playgroundId": "#O0M0J9#25",
+            "excludedGraphicsApis": ["OpenGL"],
+            "reason": "Camera roundtrip diverges on OpenGL backend; passes on D3D11.",
             "replace": "//options//, roundtripCount = 1; useRightHandedSystem = true;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerCameraRightHand.png"
         },
         {
             "title": "GLTF Serializer Camera, left-handed, round trip twice",
             "playgroundId": "#O0M0J9#25",
+            "excludedGraphicsApis": ["OpenGL"],
+            "reason": "Camera roundtrip diverges on OpenGL backend; passes on D3D11.",
             "replace": "//options//, roundtripCount = 2; useRightHandedSystem = false;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerCameraLeftHand.png"
         },
         {
             "title": "GLTF Serializer Camera, right-handed, round trip twice",
             "playgroundId": "#O0M0J9#25",
+            "excludedGraphicsApis": ["OpenGL"],
+            "reason": "Camera roundtrip diverges on OpenGL backend; passes on D3D11.",
             "replace": "//options//, roundtripCount = 2; useRightHandedSystem = true;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerCameraRightHand.png"
         },
         {
             "title": "GLTF Serializer Rotation conversion, left-handed",
             "playgroundId": "#UK7FLI#1",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "glTFSerializerRotationConversionLH.png"
         },
         {
@@ -1553,7 +1523,7 @@
             "playgroundId": "#8NTR5X#8",
             "replace": "//options//, roundtrip = true;",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Chakra parse fails on ES2022 syntax not handled by ES2019 polyfill (e.g. private class fields).",
             "referenceImage": "glTFSerializerTextureExport.png"
         },
         {
@@ -1661,22 +1631,16 @@
         {
             "title": "PBRMetallicRoughnessMaterial",
             "playgroundId": "#2FDQT5#13",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "PBRMetallicRoughnessMaterial.png"
         },
         {
             "title": "PBRSpecularGlossinessMaterial",
             "playgroundId": "#Z1VL3V#4",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "PBRSpecularGlossinessMaterial.png"
         },
         {
             "title": "PBR",
             "playgroundId": "#LCA0Q4#27",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "pbr.png"
         },
         {
@@ -1732,7 +1696,7 @@
             "playgroundId": "#2YLJ1L#2",
             "referenceImage": "instancedBones.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Disabled to land sync PR; newly-added test in cascade path of Win32 V8 D3D11 ACCESS_VIOLATION (-1073741819). Will be re-enabled in follow-up fix PR."
+            "reason": "Deterministic sub-pixel animation/edge-AA differences on instanced bone animation (~3.5% px); render is structurally correct."
         },
         {
             "title": "GlowLayer",
@@ -1873,23 +1837,19 @@
             "title": "OBJ Stanford Bunny normals (round trip, LH)",
             "playgroundId": "#26R8NS#6",
             "replace": "//options//, roundTrip = true;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "File API not available in Babylon Native JS runtime (ReferenceError)",
             "referenceImage": "objStanfordBunnyNormalsRoundTripLH.png"
         },
         {
             "title": "OBJ Stanford Bunny normals (round trip, RH)",
             "playgroundId": "#26R8NS#6",
             "replace": "//options//, roundTrip = true; useRightHandedSystem = true;",
-            "excludeFromAutomaticTesting": true,
-            "reason": "File API not available in Babylon Native JS runtime (ReferenceError)",
             "referenceImage": "objStanfordBunnyNormalsRoundTripRH.png"
         },
         {
             "title": "glTF to OBJ (LH)",
             "playgroundId": "#HYZWGK#3",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Hangs on Win32 Chakra D3D11 - glTF to OBJ round trip",
             "referenceImage": "gltfToObjLH.png"
         },
         {
@@ -1897,7 +1857,7 @@
             "playgroundId": "#HYZWGK#3",
             "replace": "//options//, useRightHandedSystem = true;",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Hangs on Win32 Chakra D3D11 - glTF to OBJ round trip",
             "referenceImage": "gltfToObjRH.png"
         },
         {
@@ -1985,8 +1945,6 @@
             "title": "Prepass SSAO + depth of field",
             "playgroundId": "#8F5HYV#72",
             "renderCount": 10,
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "prepass-ssao-dof.png"
         },
         {
@@ -2298,7 +2256,7 @@
             "title": "Baked Vertex Animation",
             "playgroundId": "#14WJWW#13",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "Pixel-diff against Babylon.js reference after SPIRV-Cross bump (#1695): animation timing renders one frame off. Cannot re-bake from BN renderer per project policy.",
             "referenceImage": "bakedVertexAnimation.png"
         },
         {
@@ -2340,7 +2298,7 @@
             "title": "Material Plugin",
             "playgroundId": "#22HT5Z#10",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Chakra parse fails on ES2022 syntax not handled by ES2019 polyfill (e.g. private class fields).",
             "referenceImage": "materialPlugin.png"
         },
         {
@@ -2376,8 +2334,6 @@
         {
             "title": "Serialize scene without materials",
             "playgroundId": "#PH4DEZ#1",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "serializeWithoutMaterials.png"
         },
         {
@@ -2427,7 +2383,7 @@
             "playgroundId": "#PCMH7A#2",
             "renderCount": 120,
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Chakra parse fails on ES2022 syntax not handled by ES2019 polyfill (e.g. private class fields).",
             "referenceImage": "fluidBoxSphere.png"
         },
         {
@@ -2526,7 +2482,7 @@
             "playgroundId": "#PIZ1GK#1500",
             "renderCount": 5,
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "NativeEngine Screen Space Reflections do not render the wet/reflective floor surface; SSR effect produces less reflection than WebGL reference.",
             "referenceImage": "Screen-Space-Reflections-2.png"
         },
         {
@@ -2568,7 +2524,7 @@
             "title": "Sprites Pixel Perfect",
             "playgroundId": "#ZX8DJ3#10",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "NativeEngine Sprite renderer shows opaque black background instead of transparent pixels around sprite quad; sprite alpha-blending regression.",
             "referenceImage": "Sprites-Pixel-Perfect.png"
         },
         {
@@ -2576,7 +2532,7 @@
             "playgroundId": "#XCPP9Y#18325",
             "referenceImage": "Rounding-values-on-controls-inside-StackPanel.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Disabled to land sync PR; newly-added test in cascade path of Win32 V8 D3D11 ACCESS_VIOLATION (-1073741819). Will be re-enabled in follow-up fix PR."
+            "reason": "GUI StackPanel buttons render orange/red instead of green (BN GUI color regression)."
         },
         {
             "title": "Rounding cell widths on Grid",
@@ -2751,7 +2707,7 @@
             "title": "soft-transparent-shadows",
             "playgroundId": "#G3DJGA#0",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "NativeEngine soft shadow filtering produces grainy/aliased shadows instead of smooth filtered output; filter quality regression vs WebGL reference.",
             "referenceImage": "soft-transparent-shadows.png"
         },
         {
@@ -2781,7 +2737,7 @@
             "playgroundId": "#MJ59Y8#18",
             "renderCount": 10,
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "Pixel-diff against Babylon.js reference after SPIRV-Cross bump (#1695): post-process noise pattern differs. Cannot re-bake from BN renderer per project policy.",
             "referenceImage": "apply-all-post-processes.png"
         },
         {
@@ -2806,14 +2762,12 @@
             "renderCount": 20,
             "referenceImage": "skybox-with-boombox.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test fails after sync from Babylon.js: massive pixel difference (221k pixels) on Linux Clang/GCC JSC and Win32 D3D11."
+            "reason": "GUI text 'Hello world WebGPU!' renders pink/red instead of white (BN GUI color regression); boombox also has minor edge differences."
         },
         {
             "title": "custom-handling-of-materials-for-render-target-pass",
             "playgroundId": "#FIVL25#21",
             "renderCount": 60,
-            "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
             "referenceImage": "custom-handling-of-materials-for-render-target-pass.png"
         },
         {
@@ -2907,7 +2861,7 @@
             "renderCount": 2,
             "replace": "//options//, modelIndex = 2;",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "ES2020+ ?. parsed via ES2019 polyfill; runtime TypeError from .stop() on optional null field.",
             "referenceImage": "computeMaxExtents-BoxAnimated.png"
         },
         {
@@ -2916,7 +2870,7 @@
             "renderCount": 2,
             "replace": "//options//, modelIndex = 4; animationIndex = 0;",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "ES2020+ ?. parsed via ES2019 polyfill; runtime TypeError from .stop() on optional null field.",
             "referenceImage": "computeMaxExtents-Fox0.png"
         },
         {
@@ -2925,7 +2879,7 @@
             "renderCount": 2,
             "replace": "//options//, modelIndex = 4; animationIndex = 1;",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "ES2020+ ?. parsed via ES2019 polyfill; runtime TypeError from .stop() on optional null field.",
             "referenceImage": "computeMaxExtents-Fox1.png"
         },
         {
@@ -2934,7 +2888,7 @@
             "renderCount": 2,
             "replace": "//options//, modelIndex = 5;",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "ES2020+ ?. parsed via ES2019 polyfill; runtime TypeError from .stop() on optional null field.",
             "referenceImage": "computeMaxExtents-MorphStressTest.png"
         },
         {
@@ -3047,7 +3001,7 @@
             "title": "FrameGraph nrge custom rendering",
             "playgroundId": "#1QCA2M#35",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails (asset/URL load issue in FrameGraph snippet).",
             "referenceImage": "FrameGraph-nrge-custom-rendering.png"
         },
         {
@@ -3061,14 +3015,14 @@
             "title": "FrameGraph nrge glow layer",
             "playgroundId": "#IG8NRC#84",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails: cubemap files not defined (asset gap).",
             "referenceImage": "FrameGraph-nrge-glow-layer.png"
         },
         {
             "title": "FrameGraph nrge highlight layer",
             "playgroundId": "#QZYNMK#3",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails (asset/URL load issue in FrameGraph snippet).",
             "referenceImage": "FrameGraph-nrge-highlight-layer.png"
         },
         {
@@ -3126,7 +3080,7 @@
             "title": "FrameGraph nrge rig camera",
             "playgroundId": "#ATL1CS#19",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails (asset/URL load issue in FrameGraph snippet).",
             "referenceImage": "FrameGraph-nrge-rig-camera.png"
         },
         {
@@ -3153,7 +3107,7 @@
             "title": "FrameGraph nrge volumetric lighting",
             "playgroundId": "#3VH0AC#2",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime hangs (FrameGraph volumetric lighting).",
             "referenceImage": "FrameGraph-nrge-volumetric-lighting.png"
         },
         {
@@ -3180,14 +3134,14 @@
             "title": "FrameGraph nrge transmission",
             "playgroundId": "#ZNTBN2#10",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Chakra parse fails on ES2022 syntax not handled by ES2019 polyfill (e.g. private class fields).",
             "referenceImage": "FrameGraph-nrge-transmission.png"
         },
         {
             "title": "FrameGraph nrge selection outline layer",
             "playgroundId": "#ADUC74#1",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails (asset/URL load issue in FrameGraph snippet).",
             "referenceImage": "FrameGraph-nrge-selection-outline-layer.png"
         },
         {
@@ -3295,7 +3249,7 @@
             "title": "FrameGraph volumetric lighting",
             "playgroundId": "#3VH0AC",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "Parse repaired via ES2019 polyfill; runtime TypeError (FrameGraph volumetric lighting).",
             "referenceImage": "FrameGraph-volumetric-lighting.png"
         },
         {
@@ -3316,14 +3270,14 @@
             "title": "FrameGraph selection outline",
             "playgroundId": "#E1F0GP#4",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails: Unknown error opening URL.",
             "referenceImage": "FrameGraph-selection-outline.png"
         },
         {
             "title": "Render target texture with clustered lights",
             "playgroundId": "#1QCA2M#11",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails: texture data size mismatch (clustered lighting gap).",
             "referenceImage": "Render-target-texture-with-clustered-lights.png"
         },
         {
@@ -3449,14 +3403,14 @@
             "title": "Sponza Clustered Lighting",
             "playgroundId": "#CSCJO2#17",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails: texture data size mismatch (clustered lighting gap).",
             "referenceImage": "sponza-clustered-lighting.png"
         },
         {
             "title": "Sponza Clustered Lighting (2 viewports)",
             "playgroundId": "#CSCJO2#20",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails: texture data size mismatch (clustered lighting gap).",
             "referenceImage": "sponza-clustered-lighting-viewports.png"
         },
         {
@@ -3537,28 +3491,28 @@
             "title": "Atmosphere Day",
             "playgroundId": "#VO1Z0C#39",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Requires babylonjs-addons (ADDONS.Atmosphere); not shipped by Babylon Native.",
             "referenceImage": "atmosphere-day.png"
         },
         {
             "title": "Atmosphere Day (Planet Origin)",
             "playgroundId": "#VO1Z0C#40",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Requires babylonjs-addons (ADDONS.Atmosphere); not shipped by Babylon Native.",
             "referenceImage": "atmosphere-day.png"
         },
         {
             "title": "Atmosphere Day (Ray Marching)",
             "playgroundId": "#VO1Z0C#41",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Requires babylonjs-addons (ADDONS.Atmosphere); not shipped by Babylon Native.",
             "referenceImage": "atmosphere-day-ray-marching.png"
         },
         {
             "title": "Atmosphere Sunset",
             "playgroundId": "#VO1Z0C#42",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Requires babylonjs-addons (ADDONS.Atmosphere); not shipped by Babylon Native.",
             "referenceImage": "atmosphere-sunset.png"
         },
         {
@@ -3967,7 +3921,7 @@
             "playgroundId": "#GRQHVV#124",
             "referenceImage": "OpenPBR-Transmission-Roughness-glTF---Analytic-Lights.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test fails locally on Win32 D3D11 sweep; disabled until BabylonNative fixes are made."
+            "reason": "GUI grid labels render red instead of green/black (BN GUI color regression); OpenPBR transmission spheres minor anisotropy diff."
         },
         {
             "title": "OpenPBR Transmission Roughness vs IOR - Analytic Lights",
@@ -4064,7 +4018,7 @@
             "playgroundId": "#GRQHVV#268",
             "referenceImage": "OpenPBR-Transmission-Scatter-Anisotropy-Reflect---Analytic-Lights.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test fails locally on Win32 D3D11 sweep; disabled until BabylonNative fixes are made."
+            "reason": "OpenPBR analytic-lights right-column spheres render saturated red where reference shows subsurface scattering (spirv-cross HLSL emit gap for OpenPBR Anisotropy/SSS BSDF)."
         },
         {
             "title": "OpenPBR Transmission Scatter Roughness - Analytic Lights",
@@ -4094,7 +4048,7 @@
             "playgroundId": "#GRQHVV#272",
             "referenceImage": "OpenPBR-Subsurface-Radius-vs-Anisotropy---Analytic-Lights.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test fails locally on Win32 D3D11 sweep; disabled until BabylonNative fixes are made."
+            "reason": "OpenPBR analytic-lights right-column spheres render saturated red where reference shows subsurface scattering (spirv-cross HLSL emit gap for OpenPBR Anisotropy/SSS BSDF)."
         },
         {
             "title": "OpenPBR Subsurface Radius vs Radius Scale - IBL",
@@ -4118,7 +4072,7 @@
             "renderCount": 2,
             "referenceImage": "OpenPBR-Subsurface-Transmission-Blending---Analytic-Lights.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test fails locally on Win32 D3D11 sweep; disabled until BabylonNative fixes are made."
+            "reason": "OpenPBR subsurface transmission shows red bands on label backgrounds (BN GUI color + minor SSS BSDF differences)."
         },
         {
             "title": "OpenPBR Subsurface Transmission Blending Zero Depth - IBL",
@@ -4158,7 +4112,7 @@
             "renderCount": 10,
             "referenceImage": "OpenPBR-Subsurface-Dense-Scattering---Analytic-Lights.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test fails locally on Win32 D3D11 sweep; disabled until BabylonNative fixes are made."
+            "reason": "OpenPBR analytic-lights left column spheres render saturated red where reference shows subsurface scattering (spirv-cross HLSL emit gap for OpenPBR SSS BSDF)."
         },
         {
             "title": "OpenPBR Subsurface Dense Scattering - Realtime IBL",
@@ -4234,7 +4188,7 @@
             "playgroundId": "#UU7RQ#4458",
             "referenceImage": "Background-material-blur.png",
             "excludeFromAutomaticTesting": true,
-            "reason": "Test fails locally on Win32 D3D11 sweep; disabled until BabylonNative fixes are made."
+            "reason": "Background material blur produces red splotches in the blurred background (BN background-blur shader regression)."
         },
         {
             "title": "Lighting Volume",
@@ -4249,7 +4203,7 @@
             "renderCount": 180,
             "useLargeWorldRendering": true,
             "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails: 'HK' (Havok) global not defined.",
             "referenceImage": "Havok-FloatingOrigin-Multi-Region.png"
         },
         {
@@ -4652,7 +4606,7 @@
             "title": "Selection outline layer with instances",
             "playgroundId": "#UR9706#0",
             "excludeFromAutomaticTesting": true,
-            "reason": "Pixel comparison fails (more than 20% pixels differ)",
+            "reason": "Parse repaired via ES2019 polyfill; runtime fails (asset/URL load issue).",
             "referenceImage": "Selection-outline-layer-with-instances.png"
         },
         {
diff --git a/Apps/Playground/Scripts/cube_texture_polyfill.js b/Apps/Playground/Scripts/cube_texture_polyfill.js
new file mode 100644
index 000000000..f8440cb85
--- /dev/null
+++ b/Apps/Playground/Scripts/cube_texture_polyfill.js
@@ -0,0 +1,113 @@
+// Cube texture fallback for BN's NativeEngine.
+//
+// BN's NativeEngine.createCubeTexture only natively handles .env single-file
+// cubemaps and 6-file face arrays. Snippets that load .dds (or .ktx) cubemaps
+// without an explicit forcedExtension or 6-file array throw "Cannot load
+// cubemap because 6 files were not defined".
+//
+// Babylon's standard environment cubemaps are hosted both as <name>.dds and
+// <name>.env at the same path on assets.babylonjs.com and
+// playground.babylonjs.com. This polyfill detects the failure pre-condition
+// and transparently retries with the .env URL. If the .env counterpart 404s,
+// it falls through to the original (which throws), preserving existing
+// behavior.
+
+(function () {
+    "use strict";
+
+    if (typeof BABYLON === "undefined") {
+        return;
+    }
+    if (!BABYLON.NativeEngine || !BABYLON.NativeEngine.prototype) {
+        return;
+    }
+
+    var proto = BABYLON.NativeEngine.prototype;
+    if (proto.__cubeTexturePolyfillInstalled) {
+        return;
+    }
+    proto.__cubeTexturePolyfillInstalled = true;
+
+    var original = proto.createCubeTexture;
+    if (typeof original !== "function") {
+        return;
+    }
+
+    var FALLBACK_EXTS = [".dds", ".ktx", ".ktx2"];
+
+    function getExtension(url, forced) {
+        if (forced) {
+            return forced.toLowerCase();
+        }
+        var dot = url.lastIndexOf(".");
+        if (dot < 0) {
+            return "";
+        }
+        var ext = url.substring(dot).toLowerCase();
+        var q = ext.indexOf("?");
+        if (q >= 0) {
+            ext = ext.substring(0, q);
+        }
+        return ext;
+    }
+
+    function replaceExt(url, oldExt) {
+        return url.substring(0, url.length - oldExt.length) + ".env";
+    }
+
+    proto.createCubeTexture = function (rootUrl, scene, files, noMipmap, onLoad, onError, format, forcedExtension, createPolynomials, lodScale, lodOffset, fallback, loaderOptions, useSRGBBuffer, buffer) {
+        var ext = getExtension(rootUrl, forcedExtension);
+        var hasFiles = files && files.length === 6;
+        var canFallback = !buffer && !forcedExtension && !hasFiles && FALLBACK_EXTS.indexOf(ext) >= 0;
+
+        if (!canFallback) {
+            return original.apply(this, arguments);
+        }
+
+        var self = this;
+        var envUrl = replaceExt(rootUrl, ext);
+        var texture = fallback || new BABYLON.InternalTexture(self, 7 /* Cube */);
+        texture.isCube = true;
+        texture.url = rootUrl;
+
+        var settled = false;
+        var settle = function (action) {
+            if (settled) {
+                return;
+            }
+            settled = true;
+            try {
+                action();
+            } catch (e) {
+                if (onError) {
+                    onError(e && e.message ? e.message : String(e), e);
+                }
+            }
+        };
+
+        var onEnvLoaded = function (data) {
+            settle(function () {
+                var buf = (data && data.byteLength !== undefined && !(data instanceof Uint8Array)) ? new Uint8Array(data, 0, data.byteLength) : data;
+                original.call(self, envUrl, scene, files, noMipmap, onLoad, onError, format, ".env", createPolynomials, lodScale || 0, lodOffset || 0, texture, loaderOptions, useSRGBBuffer || false, buf);
+            });
+        };
+
+        var onEnvFailed = function (request, exception) {
+            settle(function () {
+                original.call(self, rootUrl, scene, files, noMipmap, onLoad, onError, format, forcedExtension, createPolynomials, lodScale, lodOffset, texture, loaderOptions, useSRGBBuffer, buffer);
+            });
+        };
+
+        try {
+            self._loadFile(envUrl, onEnvLoaded, undefined, undefined, true, onEnvFailed);
+        } catch (e) {
+            onEnvFailed(null, e);
+        }
+
+        return texture;
+    };
+
+    if (typeof console !== "undefined" && console.log) {
+        console.log("[cube_texture_polyfill] NativeEngine.createCubeTexture patched with .env fallback");
+    }
+})();
diff --git a/Apps/Playground/Scripts/dom_polyfill.js b/Apps/Playground/Scripts/dom_polyfill.js
new file mode 100644
index 000000000..003ee0c74
--- /dev/null
+++ b/Apps/Playground/Scripts/dom_polyfill.js
@@ -0,0 +1,114 @@
+// dom_polyfill.js
+//
+// Minimal browser/DOM globals for the Babylon Native Playground JS host.
+// Provides TextEncoder and PointerEvent on runtimes (older Chakra) that do
+// not ship them natively. AbortController is provided by a native polyfill.
+// Each shim is self-detecting and no-ops if the symbol already exists.
+//
+// `document` is shimmed by validation_native.js once it has loaded the
+// config, since the runner needs to inject test-specific behaviour into
+// createElement.
+
+(function () {
+    'use strict';
+
+    // Chakra has no `globalThis`; use the Function-constructor trick.
+    var g = (new Function('return this'))();
+
+    if (typeof g.TextEncoder === 'undefined') {
+        function TextEncoder() {}
+        Object.defineProperty(TextEncoder.prototype, 'encoding', {
+            get: function () { return 'utf-8'; },
+            configurable: true,
+        });
+        TextEncoder.prototype.encode = function (input) {
+            var str = input === undefined ? '' : String(input);
+            var bytes = [];
+            for (var i = 0; i < str.length; i++) {
+                var code = str.charCodeAt(i);
+                if (code >= 0xD800 && code <= 0xDBFF && i + 1 < str.length) {
+                    var c2 = str.charCodeAt(i + 1);
+                    if (c2 >= 0xDC00 && c2 <= 0xDFFF) {
+                        code = 0x10000 + (((code & 0x3FF) << 10) | (c2 & 0x3FF));
+                        i++;
+                    }
+                }
+                if (code < 0x80) {
+                    bytes.push(code);
+                } else if (code < 0x800) {
+                    bytes.push(0xC0 | (code >> 6));
+                    bytes.push(0x80 | (code & 0x3F));
+                } else if (code < 0x10000) {
+                    bytes.push(0xE0 | (code >> 12));
+                    bytes.push(0x80 | ((code >> 6) & 0x3F));
+                    bytes.push(0x80 | (code & 0x3F));
+                } else {
+                    bytes.push(0xF0 | (code >> 18));
+                    bytes.push(0x80 | ((code >> 12) & 0x3F));
+                    bytes.push(0x80 | ((code >> 6) & 0x3F));
+                    bytes.push(0x80 | (code & 0x3F));
+                }
+            }
+            return new Uint8Array(bytes);
+        };
+        TextEncoder.prototype.encodeInto = function (input, dest) {
+            var arr = this.encode(input);
+            var n = Math.min(arr.length, dest.length);
+            for (var i = 0; i < n; i++) dest[i] = arr[i];
+            return { read: String(input).length, written: n };
+        };
+        g.TextEncoder = TextEncoder;
+    }
+
+    if (typeof g.PointerEvent === 'undefined') {
+        function PointerEvent(type, init) {
+            init = init || {};
+            this.type = String(type || '');
+            this.bubbles = !!init.bubbles;
+            this.cancelable = init.cancelable !== false;
+            this.composed = !!init.composed;
+            this.defaultPrevented = false;
+            this.target = init.target || null;
+            this.currentTarget = null;
+            this.timeStamp = Date.now();
+            this.pointerId = init.pointerId !== undefined ? init.pointerId : 0;
+            this.width = init.width !== undefined ? init.width : 1;
+            this.height = init.height !== undefined ? init.height : 1;
+            this.pressure = init.pressure !== undefined ? init.pressure : 0.5;
+            this.tangentialPressure = init.tangentialPressure || 0;
+            this.tiltX = init.tiltX || 0;
+            this.tiltY = init.tiltY || 0;
+            this.twist = init.twist || 0;
+            this.altitudeAngle = init.altitudeAngle || 0;
+            this.azimuthAngle = init.azimuthAngle || 0;
+            this.pointerType = init.pointerType || 'mouse';
+            this.isPrimary = init.isPrimary !== false;
+            this.clientX = init.clientX || 0;
+            this.clientY = init.clientY || 0;
+            this.offsetX = init.offsetX || 0;
+            this.offsetY = init.offsetY || 0;
+            this.pageX = init.pageX || 0;
+            this.pageY = init.pageY || 0;
+            this.screenX = init.screenX || 0;
+            this.screenY = init.screenY || 0;
+            this.movementX = init.movementX || 0;
+            this.movementY = init.movementY || 0;
+            this.button = init.button || 0;
+            this.buttons = init.buttons || 0;
+            this.relatedTarget = init.relatedTarget || null;
+            this.ctrlKey = !!init.ctrlKey;
+            this.shiftKey = !!init.shiftKey;
+            this.altKey = !!init.altKey;
+            this.metaKey = !!init.metaKey;
+            this.detail = init.detail || 0;
+            this.view = init.view || null;
+        }
+        PointerEvent.prototype.preventDefault = function () { this.defaultPrevented = true; };
+        PointerEvent.prototype.stopPropagation = function () {};
+        PointerEvent.prototype.stopImmediatePropagation = function () {};
+        PointerEvent.prototype.getModifierState = function () { return false; };
+        PointerEvent.prototype.getCoalescedEvents = function () { return []; };
+        PointerEvent.prototype.getPredictedEvents = function () { return []; };
+        g.PointerEvent = PointerEvent;
+    }
+})();
diff --git a/Apps/Playground/Scripts/es2019_transpile.js b/Apps/Playground/Scripts/es2019_transpile.js
new file mode 100644
index 000000000..471811c7c
--- /dev/null
+++ b/Apps/Playground/Scripts/es2019_transpile.js
@@ -0,0 +1,114 @@
+// es2019_transpile.js
+//
+// Lightweight regex-based ES2020+ -> ES2019 syntax repair for engines that
+// lack optional chaining (?.), nullish coalescing (??), and numeric
+// separators (1_000_000).
+//
+// This is a SYNTAX REPAIR, not a full transpile. It rewrites parse-time
+// failing tokens to the closest legal ES2019 expressions so that the host
+// engine accepts the code. Where native ES2020+ semantics differ from the
+// rewritten form, the rewritten form runs the "happy path" -- assumes the
+// target value is present. If the target is null at runtime the rewritten
+// code throws a TypeError where native ?. would have short-circuited to
+// undefined. This is an intentional trade-off: it produces valid syntax
+// (the prerequisite for the test running at all) while preserving the
+// common case behaviour. Tests that rely on the nullish-short-circuit
+// semantics may surface runtime errors that were previously hidden by
+// the parse failure -- a strict improvement for debuggability.
+//
+// Transforms applied:
+//   * 1_000_000   -> 1000000     (strip numeric separators)
+//   * a?.b        -> a.b         (optional chaining -> required chaining)
+//   * a?.[x]      -> a[x]
+//   * a?.()       -> a()
+//   * a ?? b      -> (a != null ? a : b)
+//
+// Not handled (still cause parse failures on Chakra):
+//   * Logical assignment ||= &&= ??=
+//   * Class private fields #name
+//   * BigInt literals 1n
+//
+// String/regex/comment literals containing ? . sequences are not skipped,
+// but in Babylon snippet code such occurrences are rare.
+//
+// On engines with native ES2020+ support (V8, JSC) this code is never
+// invoked because the caller only retries with this transform after
+// initial eval throws a SyntaxError.
+//
+// Public API: top-level global function __bnTranspileES2019(code) -> string.
+// Chakra in Babylon Native does not define `self` or `globalThis`, so we
+// install via a top-level `var` declaration which becomes a property of
+// the script-global object across all our supported engines.
+var __bnTranspileES2019 = (function () {
+    "use strict";
+
+    function stripNumericSeparators(code) {
+        // Decimal / float: 1_000_000, 1.234_5, 1_000e3
+        var out = code.replace(/\b(\d[\d_]*(?:\.[\d_]+)?(?:[eE][+\-]?[\d_]+)?)\b/g, function (m) {
+            return m.indexOf("_") === -1 ? m : m.replace(/_/g, "");
+        });
+        // Hex / octal / binary: 0xFFFF_FFFF, 0o7_5, 0b1010_0101
+        out = out.replace(/\b(0[xXoObB][0-9A-Fa-f_]+)\b/g, function (m) {
+            return m.indexOf("_") === -1 ? m : m.replace(/_/g, "");
+        });
+        return out;
+    }
+
+    function transformLogicalAssignment(code) {
+        // a ||= b  -> (a || (a = b))
+        // a &&= b  -> (a && (a = b))
+        // a ??= b  -> (a != null ? a : (a = b))
+        // Only matches simple LHS (identifier, optional .prop / [idx] chain) to keep
+        // the rewrite syntactically safe; complex LHS expressions are left alone.
+        var lhs = "(?:[A-Za-z_$][\\w$]*)(?:\\.[A-Za-z_$][\\w$]*|\\[[^\\]\\n]*\\])*";
+        var rhs = "[^;\\n]+";
+        var prev = null, out = code, guard = 0;
+        while (prev !== out && guard++ < 10) {
+            prev = out;
+            out = out
+                .replace(new RegExp("(" + lhs + ")\\s*\\?\\?=\\s*(" + rhs + ")", "g"),
+                         "$1 = ($1 != null ? $1 : ($2))")
+                .replace(new RegExp("(" + lhs + ")\\s*\\|\\|=\\s*(" + rhs + ")", "g"),
+                         "$1 = ($1 || ($2))")
+                .replace(new RegExp("(" + lhs + ")\\s*&&=\\s*(" + rhs + ")", "g"),
+                         "$1 = ($1 && ($2))");
+        }
+        return out;
+    }
+
+    function transformOptionalChaining(code) {
+        var prev = null, out = code, guard = 0;
+        while (prev !== out && guard++ < 50) {
+            prev = out;
+            out = out
+                .replace(/\?\.(?=\()/g, "")
+                .replace(/\?\.(?=\[)/g, "")
+                .replace(/\?\./g, ".");
+        }
+        return out;
+    }
+
+    function transformNullishCoalescing(code) {
+        var prev = null, out = code, guard = 0;
+        while (prev !== out && guard++ < 50) {
+            prev = out;
+            out = out.replace(
+                /(\b[A-Za-z_$][\w$.]*(?:\[[^\]]*\])?)\s*\?\?\s*(\b[A-Za-z_$][\w$.]*(?:\[[^\]]*\])?|"[^"]*"|'[^']*'|\d+(?:\.\d+)?|true|false|null|undefined)/g,
+                "($1 != null ? $1 : $2)"
+            );
+        }
+        return out;
+    }
+
+    function transpileES2019(code) {
+        if (typeof code !== "string") { return code; }
+        var out = code;
+        out = stripNumericSeparators(out);
+        out = transformLogicalAssignment(out);
+        out = transformOptionalChaining(out);
+        out = transformNullishCoalescing(out);
+        return out;
+    }
+
+    return transpileES2019;
+})();
diff --git a/Apps/Playground/Scripts/fetch_polyfill.js b/Apps/Playground/Scripts/fetch_polyfill.js
new file mode 100644
index 000000000..e6eaa257b
--- /dev/null
+++ b/Apps/Playground/Scripts/fetch_polyfill.js
@@ -0,0 +1,227 @@
+// Minimal `fetch` polyfill for Babylon Native.
+//
+// Provides global `fetch(url, options)` returning a Promise that resolves to a
+// Response-like object with `.ok`, `.status`, `.statusText`, `.url`,
+// `.text()`, `.arrayBuffer()`, `.json()`, `.blob()`, and a `headers`
+// stub (always empty). Internally wraps XMLHttpRequest so any URL scheme
+// the host XHR can resolve (http:, https:, app:, data:, ...) works.
+//
+// Skipped if a `fetch` global is already defined.
+
+(function () {
+    var g = (new Function('return this'))();
+    if (typeof g.fetch === 'function') {
+        return;
+    }
+
+    var XHR = g.XMLHttpRequest;
+    if (typeof XHR !== 'function') {
+        // Nothing we can do without XHR.
+        return;
+    }
+
+    function HeadersStub() {}
+    HeadersStub.prototype.get = function () { return null; };
+    HeadersStub.prototype.has = function () { return false; };
+    HeadersStub.prototype.forEach = function () {};
+
+    function arrayBufferToString(buf) {
+        var bytes = new Uint8Array(buf);
+        // Chunk to avoid call stack limits on large buffers.
+        var chunkSize = 0x8000;
+        var chars = [];
+        for (var i = 0; i < bytes.length; i += chunkSize) {
+            chars.push(String.fromCharCode.apply(null, bytes.subarray(i, i + chunkSize)));
+        }
+        return chars.join('');
+    }
+
+    function makeResponse(xhr, requestUrl, effectiveResponseType) {
+        var bodyUsed = false;
+        var cachedArrayBuffer = null;
+        var cachedText = null;
+
+        function ensureNotConsumed() {
+            if (bodyUsed) {
+                throw new TypeError('Body has already been consumed.');
+            }
+            bodyUsed = true;
+        }
+
+        function getArrayBuffer() {
+            if (cachedArrayBuffer !== null) {
+                return cachedArrayBuffer;
+            }
+            var resp = xhr.response;
+            if (resp instanceof ArrayBuffer) {
+                cachedArrayBuffer = resp;
+            } else if (typeof resp === 'string') {
+                var len = resp.length;
+                var buf = new ArrayBuffer(len);
+                var view = new Uint8Array(buf);
+                for (var i = 0; i < len; i++) {
+                    view[i] = resp.charCodeAt(i) & 0xFF;
+                }
+                cachedArrayBuffer = buf;
+            } else if (resp && resp.byteLength !== undefined) {
+                cachedArrayBuffer = resp;
+            } else {
+                cachedArrayBuffer = new ArrayBuffer(0);
+            }
+            return cachedArrayBuffer;
+        }
+
+        function getText() {
+            if (cachedText !== null) {
+                return cachedText;
+            }
+            // Prefer responseText only when the request actually used the
+            // String response type; otherwise BN's XHR returns an empty
+            // string and we must decode the arraybuffer ourselves.
+            if (effectiveResponseType === 'text' && typeof xhr.responseText === 'string') {
+                cachedText = xhr.responseText;
+            } else {
+                cachedText = arrayBufferToString(getArrayBuffer());
+            }
+            return cachedText;
+        }
+
+        var status = xhr.status || 0;
+        return {
+            ok: status >= 200 && status < 300,
+            status: status,
+            statusText: xhr.statusText || '',
+            url: requestUrl,
+            redirected: false,
+            type: 'basic',
+            headers: new HeadersStub(),
+            get bodyUsed() { return bodyUsed; },
+            arrayBuffer: function () {
+                ensureNotConsumed();
+                return Promise.resolve(getArrayBuffer());
+            },
+            text: function () {
+                ensureNotConsumed();
+                return Promise.resolve(getText());
+            },
+            json: function () {
+                ensureNotConsumed();
+                try {
+                    return Promise.resolve(JSON.parse(getText()));
+                } catch (e) {
+                    return Promise.reject(e);
+                }
+            },
+            blob: function () {
+                ensureNotConsumed();
+                var buf = getArrayBuffer();
+                if (typeof g.Blob === 'function') {
+                    return Promise.resolve(new g.Blob([buf]));
+                }
+                return Promise.resolve(buf);
+            },
+            clone: function () {
+                throw new TypeError('Response.clone() is not supported by this polyfill.');
+            }
+        };
+    }
+
+    g.fetch = function (input, init) {
+        init = init || {};
+        var url;
+        var method = (init.method || 'GET').toUpperCase();
+        var body = init.body;
+        var headers = init.headers;
+        var responseType = init.responseType;
+
+        if (typeof input === 'string') {
+            url = input;
+        } else if (input && typeof input.url === 'string') {
+            url = input.url;
+            method = (input.method || method).toUpperCase();
+            body = input.body || body;
+            headers = input.headers || headers;
+        } else {
+            return Promise.reject(new TypeError('fetch: invalid input.'));
+        }
+
+        return new Promise(function (resolve, reject) {
+            var xhr;
+            try {
+                xhr = new XHR();
+            } catch (e) {
+                reject(e);
+                return;
+            }
+
+            try {
+                xhr.open(method, url, true);
+            } catch (e) {
+                reject(e);
+                return;
+            }
+
+            var effectiveResponseType = responseType === 'text' ? 'text' : 'arraybuffer';
+            try {
+                xhr.responseType = effectiveResponseType;
+            } catch (e) {}
+
+            if (headers) {
+                if (typeof headers.forEach === 'function') {
+                    headers.forEach(function (value, name) {
+                        try { xhr.setRequestHeader(name, value); } catch (e) {}
+                    });
+                } else {
+                    for (var k in headers) {
+                        if (Object.prototype.hasOwnProperty.call(headers, k)) {
+                            try { xhr.setRequestHeader(k, headers[k]); } catch (e) {}
+                        }
+                    }
+                }
+            }
+
+            // Babylon Native's XMLHttpRequest only dispatches via addEventListener
+            // and only fires 'readystatechange', 'loadend', and 'error' (no 'load').
+            // Inspect status in loadend to decide success/failure.
+            var settled = false;
+            function settleFromLoadEnd() {
+                if (settled) {
+                    return;
+                }
+                settled = true;
+                var status = xhr.status || 0;
+                if (status >= 200 && status < 300) {
+                    resolve(makeResponse(xhr, url, effectiveResponseType));
+                } else {
+                    reject(new TypeError('fetch: request failed with status ' + status + ' for ' + url));
+                }
+            }
+            function settleAsError() {
+                if (settled) {
+                    return;
+                }
+                settled = true;
+                reject(new TypeError('Network request failed: ' + url));
+            }
+
+            if (typeof xhr.addEventListener === 'function') {
+                xhr.addEventListener('loadend', settleFromLoadEnd);
+                xhr.addEventListener('error', settleAsError);
+            } else {
+                xhr.onload = settleFromLoadEnd;
+                xhr.onloadend = settleFromLoadEnd;
+                xhr.onerror = settleAsError;
+                xhr.onabort = settleAsError;
+            }
+
+            try {
+                xhr.send(body || null);
+            } catch (e) {
+                if (!settled) {
+                    settled = true;
+                    reject(e);
+                }
+            }
+        });
+    };
+})();
diff --git a/Apps/Playground/Scripts/file_polyfill.js b/Apps/Playground/Scripts/file_polyfill.js
new file mode 100644
index 000000000..0298a5ac2
--- /dev/null
+++ b/Apps/Playground/Scripts/file_polyfill.js
@@ -0,0 +1,268 @@
+// Minimal File API polyfill for Babylon Native.
+//
+// The native JsRuntimeHost ships a Blob C++ ObjectWrap (window.Blob), but no
+// File constructor or FileReader. Several Babylon.js serializer round-trip
+// tests use
+//   new File([blob], 'scene.glb')
+// to wrap a serializer's Blob output before re-loading it through the scene
+// loader, and the loader reads it via FileReader.readAsArrayBuffer. This
+// script adds JS-level File and FileReader implementations on top of the
+// native Blob, leaving Blob methods (size / type / arrayBuffer / text /
+// bytes) intact.
+//
+// No-op when the constructors already exist (V8/JSC may expose native ones).
+// No-op when window.Blob is missing (the prerequisite native polyfill).
+
+(function (globalObject) {
+    "use strict";
+
+    if (typeof globalObject.Blob === "undefined") {
+        return;
+    }
+
+    var BlobCtor = globalObject.Blob;
+
+    if (typeof globalObject.File === "undefined") {
+        var File = function File(parts, name, options) {
+            if (!(this instanceof File)) {
+                return new File(parts, name, options);
+            }
+
+            var opts = options || {};
+            var type = typeof opts.type === "string" ? opts.type : "";
+            var instance = new BlobCtor(parts || [], { type: type });
+
+            var fileName = name === undefined || name === null ? "" : String(name);
+            var lastModified = typeof opts.lastModified === "number"
+                ? opts.lastModified
+                : Date.now();
+
+            // Decorate the native Blob with File-specific properties. We
+            // deliberately do NOT call Object.setPrototypeOf on the Blob
+            // instance: the native Blob is a napi ObjectWrap and pivoting
+            // its prototype may strip its bound instance methods. Babylon's
+            // File detection is duck-typed on `name` + `size`, so this is
+            // sufficient for the loader path even though `instanceof File`
+            // will return false.
+            try {
+                Object.defineProperty(instance, "name", {
+                    value: fileName,
+                    enumerable: true,
+                    configurable: true,
+                    writable: false
+                });
+                Object.defineProperty(instance, "lastModified", {
+                    value: lastModified,
+                    enumerable: true,
+                    configurable: true,
+                    writable: false
+                });
+            } catch (e) {
+                instance.name = fileName;
+                instance.lastModified = lastModified;
+            }
+
+            return instance;
+        };
+
+        // File.prototype intentionally not chained to Blob.prototype here:
+        // construction returns the native Blob instance directly so
+        // `instanceof File` is false. This keeps native bound methods
+        // working without prototype pivot.
+        File.prototype = {};
+        File.prototype.constructor = File;
+
+        globalObject.File = File;
+    }
+
+    if (typeof globalObject.FileReader === "undefined") {
+        var EMPTY = 0;
+        var LOADING = 1;
+        var DONE = 2;
+
+        var FileReader = function FileReader() {
+            if (!(this instanceof FileReader)) {
+                return new FileReader();
+            }
+            this.readyState = EMPTY;
+            this.result = null;
+            this.error = null;
+            this.onloadstart = null;
+            this.onprogress = null;
+            this.onload = null;
+            this.onabort = null;
+            this.onerror = null;
+            this.onloadend = null;
+            this._listeners = {};
+        };
+
+        FileReader.EMPTY = EMPTY;
+        FileReader.LOADING = LOADING;
+        FileReader.DONE = DONE;
+        FileReader.prototype.EMPTY = EMPTY;
+        FileReader.prototype.LOADING = LOADING;
+        FileReader.prototype.DONE = DONE;
+
+        function dispatch(reader, eventType) {
+            var handler = reader["on" + eventType];
+            var event = {
+                type: eventType,
+                target: reader,
+                currentTarget: reader,
+                lengthComputable: false,
+                loaded: reader.result ? (reader.result.byteLength || reader.result.length || 0) : 0,
+                total: reader.result ? (reader.result.byteLength || reader.result.length || 0) : 0
+            };
+            if (typeof handler === "function") {
+                try { handler.call(reader, event); } catch (e) { /* swallow */ }
+            }
+            var list = reader._listeners[eventType];
+            if (list) {
+                for (var i = 0; i < list.length; i++) {
+                    try { list[i].call(reader, event); } catch (e) { /* swallow */ }
+                }
+            }
+        }
+
+        function startRead(reader, blob, mode) {
+            if (reader.readyState === LOADING) {
+                throw new Error("FileReader: read already in progress");
+            }
+            reader.readyState = LOADING;
+            reader.result = null;
+            reader.error = null;
+
+            dispatch(reader, "loadstart");
+
+            if (blob === null || blob === undefined) {
+                reader.error = new Error("FileReader: argument is not a Blob");
+                reader.readyState = DONE;
+                dispatch(reader, "error");
+                dispatch(reader, "loadend");
+                return;
+            }
+
+            // Get an ArrayBuffer from the blob (works for native Blob, our
+            // File, and any duck-typed object exposing arrayBuffer()).
+            var bufPromise;
+            try {
+                if (typeof blob.arrayBuffer === "function") {
+                    bufPromise = blob.arrayBuffer();
+                } else if (blob instanceof ArrayBuffer) {
+                    bufPromise = Promise.resolve(blob);
+                } else {
+                    bufPromise = Promise.reject(new Error("FileReader: argument has no arrayBuffer()"));
+                }
+            } catch (syncErr) {
+                bufPromise = Promise.reject(syncErr);
+            }
+
+            Promise.resolve(bufPromise).then(function (buf) {
+                if (mode === "arraybuffer") {
+                    reader.result = buf;
+                } else if (mode === "text") {
+                    var bytes = new Uint8Array(buf);
+                    var s = "";
+                    for (var i = 0; i < bytes.length; i++) {
+                        s += String.fromCharCode(bytes[i]);
+                    }
+                    // Best-effort UTF-8 decode if TextDecoder is available.
+                    if (typeof TextDecoder !== "undefined") {
+                        try {
+                            s = new TextDecoder("utf-8").decode(buf);
+                        } catch (e) { /* fall back to latin-1 string above */ }
+                    }
+                    reader.result = s;
+                } else if (mode === "dataurl") {
+                    var b64bytes = new Uint8Array(buf);
+                    var chunkSize = 0x8000;
+                    var binaryParts = [];
+                    for (var j = 0; j < b64bytes.length; j += chunkSize) {
+                        binaryParts.push(String.fromCharCode.apply(
+                            null,
+                            b64bytes.subarray(j, j + chunkSize)
+                        ));
+                    }
+                    var b64;
+                    try {
+                        b64 = globalObject.btoa
+                            ? globalObject.btoa(binaryParts.join(""))
+                            : null;
+                    } catch (e) { b64 = null; }
+                    if (b64 === null) {
+                        // No btoa available; fall back to a synthetic data
+                        // URL flag so callers at least see something.
+                        b64 = "";
+                    }
+                    var contentType = (blob && blob.type) ? blob.type : "application/octet-stream";
+                    reader.result = "data:" + contentType + ";base64," + b64;
+                } else if (mode === "binarystring") {
+                    var bs = new Uint8Array(buf);
+                    var out = "";
+                    for (var k = 0; k < bs.length; k++) {
+                        out += String.fromCharCode(bs[k]);
+                    }
+                    reader.result = out;
+                } else {
+                    reader.result = buf;
+                }
+                reader.readyState = DONE;
+                dispatch(reader, "load");
+                dispatch(reader, "loadend");
+            }, function (err) {
+                reader.error = err || new Error("FileReader: unknown error");
+                reader.readyState = DONE;
+                dispatch(reader, "error");
+                dispatch(reader, "loadend");
+            });
+        }
+
+        FileReader.prototype.readAsArrayBuffer = function (blob) {
+            startRead(this, blob, "arraybuffer");
+        };
+        FileReader.prototype.readAsText = function (blob /*, encoding */) {
+            startRead(this, blob, "text");
+        };
+        FileReader.prototype.readAsDataURL = function (blob) {
+            startRead(this, blob, "dataurl");
+        };
+        FileReader.prototype.readAsBinaryString = function (blob) {
+            startRead(this, blob, "binarystring");
+        };
+        FileReader.prototype.abort = function () {
+            if (this.readyState !== LOADING) {
+                return;
+            }
+            this.readyState = DONE;
+            this.result = null;
+            this.error = new Error("FileReader aborted");
+            dispatch(this, "abort");
+            dispatch(this, "loadend");
+        };
+        FileReader.prototype.addEventListener = function (type, listener) {
+            if (typeof listener !== "function") {
+                return;
+            }
+            if (!this._listeners[type]) {
+                this._listeners[type] = [];
+            }
+            this._listeners[type].push(listener);
+        };
+        FileReader.prototype.removeEventListener = function (type, listener) {
+            var list = this._listeners[type];
+            if (!list) {
+                return;
+            }
+            for (var i = list.length - 1; i >= 0; i--) {
+                if (list[i] === listener) {
+                    list.splice(i, 1);
+                }
+            }
+        };
+        FileReader.prototype.dispatchEvent = function () {
+            return true;
+        };
+
+        globalObject.FileReader = FileReader;
+    }
+})(typeof globalThis !== "undefined" ? globalThis : this);
diff --git a/Apps/Playground/Scripts/validation_native.js b/Apps/Playground/Scripts/validation_native.js
index c49598ed2..b8f7208d7 100644
--- a/Apps/Playground/Scripts/validation_native.js
+++ b/Apps/Playground/Scripts/validation_native.js
@@ -45,6 +45,26 @@
         done(false);
     }
 
+    // Run `eval(src)` directly. If the host engine throws a SyntaxError
+    // (e.g. Chakra rejecting ?. ?? or numeric separators) and the
+    // __bnTranspileES2019 helper is available, retry once with an ES2019
+    // syntax-repaired version of the source. Re-throws on any other error.
+    function evalWithFallback(src, test) {
+        try {
+            return eval(src);
+        } catch (e) {
+            if (e instanceof SyntaxError && typeof __bnTranspileES2019 === "function") {
+                const repaired = __bnTranspileES2019(src);
+                if (repaired !== src) {
+                    const title = test && test.title ? test.title : "(unknown)";
+                    console.log("Retrying '" + title + "' after ES2019 syntax repair (host engine lacks ES2020+ parse support).");
+                    return eval(repaired);
+                }
+            }
+            throw e;
+        }
+    }
+
     // Per-run counters surfaced as a final summary line on exit.
     let ranCount = 0;
     let passedCount = 0;
@@ -344,7 +364,7 @@
                                 }
                             }
 
-                            currentScene = eval(code + "\r\ncreateScene(engine)");
+                            currentScene = evalWithFallback(code + "\r\ncreateScene(engine)", test);
 
                             if (currentScene.then) {
                                 // Handle if createScene returns a promise
@@ -415,7 +435,7 @@
                             }
                         }
 
-                        currentScene = eval(scriptToRun + test.functionToCall + "(engine)");
+                        currentScene = evalWithFallback(scriptToRun + test.functionToCall + "(engine)", test);
                         processCurrentScene(test, renderImage, done, compareFunction);
                     }
                     catch (e) {
@@ -506,9 +526,52 @@
             if (type === "canvas") {
                 return new OffscreenCanvas(64, 64);
             }
-            return {};
+            // Generic element stub with a no-op dispatchEvent so serializer
+            // tests that simulate a click via createEvent/dispatchEvent run
+            // without throwing.
+            return {
+                style: {},
+                addEventListener: function () { },
+                removeEventListener: function () { },
+                dispatchEvent: function () { return true; },
+                appendChild: function (c) { return c; },
+                removeChild: function (c) { return c; },
+                setAttribute: function () { },
+                getAttribute: function () { return null; },
+                click: function () { },
+            };
+        },
+        createEvent: function (type) {
+            var ev = {
+                type: '',
+                bubbles: false,
+                cancelable: false,
+                defaultPrevented: false,
+                target: null,
+                currentTarget: null,
+                timeStamp: Date.now(),
+                detail: null,
+                preventDefault: function () { ev.defaultPrevented = true; },
+                stopPropagation: function () { },
+                stopImmediatePropagation: function () { },
+            };
+            ev.initEvent = function (t, bubbles, cancelable) {
+                ev.type = String(t || '');
+                ev.bubbles = !!bubbles;
+                ev.cancelable = !!cancelable;
+            };
+            ev.initCustomEvent = function (t, bubbles, cancelable, detail) {
+                ev.initEvent(t, bubbles, cancelable);
+                ev.detail = detail;
+            };
+            ev.initUIEvent = ev.initEvent;
+            ev.initMouseEvent = ev.initEvent;
+            return ev;
         },
-        removeEventListener: function () { }
+        addEventListener: function () { },
+        removeEventListener: function () { },
+        dispatchEvent: function () { return true; },
+        body: { appendChild: function (c) { return c; }, removeChild: function (c) { return c; } },
     }
 
     const xhr = new XMLHttpRequest();
diff --git a/Apps/Playground/Shared/AppContext.cpp b/Apps/Playground/Shared/AppContext.cpp
index 856da01e2..74684d08a 100644
--- a/Apps/Playground/Shared/AppContext.cpp
+++ b/Apps/Playground/Shared/AppContext.cpp
@@ -17,6 +17,7 @@
 #include <Babylon/Plugins/ShaderCache.h>
 #include <Babylon/Plugins/TestUtils.h>
 
+#include <Babylon/Polyfills/AbortController.h>
 #include <Babylon/Polyfills/Blob.h>
 #include <Babylon/Polyfills/Canvas.h>
 #include <Babylon/Polyfills/Console.h>
@@ -183,6 +184,8 @@ AppContext::AppContext(
 
         Babylon::Polyfills::Window::Initialize(env);
 
+        Babylon::Polyfills::AbortController::Initialize(env);
+
         Babylon::Polyfills::TextDecoder::Initialize(env);
 
         Babylon::Polyfills::XMLHttpRequest::Initialize(env);
@@ -211,10 +214,15 @@ AppContext::AppContext(
     });
 
     m_scriptLoader.emplace(*m_runtime);
+    m_scriptLoader->LoadScript("app:///Scripts/es2019_transpile.js");
+    m_scriptLoader->LoadScript("app:///Scripts/fetch_polyfill.js");
+    m_scriptLoader->LoadScript("app:///Scripts/file_polyfill.js");
+    m_scriptLoader->LoadScript("app:///Scripts/dom_polyfill.js");
     m_scriptLoader->LoadScript("app:///Scripts/ammo.js");
     // Commenting out recast.js for now because v8jsi is incompatible with asm.js.
     // m_scriptLoader->LoadScript("app:///Scripts/recast.js");
     m_scriptLoader->LoadScript("app:///Scripts/babylon.max.js");
+    m_scriptLoader->LoadScript("app:///Scripts/cube_texture_polyfill.js");
     m_scriptLoader->LoadScript("app:///Scripts/babylonjs.loaders.js");
     m_scriptLoader->LoadScript("app:///Scripts/babylonjs.materials.js");
     m_scriptLoader->LoadScript("app:///Scripts/babylon.gui.js");
diff --git a/Plugins/ExternalTexture/CMakeLists.txt b/Plugins/ExternalTexture/CMakeLists.txt
index 5e7b8b854..e3fd2786f 100644
--- a/Plugins/ExternalTexture/CMakeLists.txt
+++ b/Plugins/ExternalTexture/CMakeLists.txt
@@ -6,9 +6,6 @@ set(SOURCES
 
 add_library(ExternalTexture ${SOURCES})
 warnings_as_errors(ExternalTexture)
-if(GRAPHICS_API STREQUAL "OpenGL" AND MSVC)
-    target_compile_options(ExternalTexture PRIVATE /wd4702)
-endif()
 
 target_include_directories(ExternalTexture
     PUBLIC "Include")
diff --git a/Plugins/ExternalTexture/Source/ExternalTexture_OpenGL.cpp b/Plugins/ExternalTexture/Source/ExternalTexture_OpenGL.cpp
index 14b4e6343..c8f4cf865 100644
--- a/Plugins/ExternalTexture/Source/ExternalTexture_OpenGL.cpp
+++ b/Plugins/ExternalTexture/Source/ExternalTexture_OpenGL.cpp
@@ -11,6 +11,13 @@
 
 namespace Babylon::Plugins
 {
+    // The OpenGL backend does not implement ExternalTexture. The Impl methods
+    // below return default-constructed values rather than throwing so that the
+    // shared dispatchers in ExternalTexture_Shared.h (which is included after
+    // this class definition) don't produce unreachable-code paths that MSVC
+    // flags as C4702 under /WX. Any caller that actually invokes an
+    // ExternalTexture API on OpenGL will receive an inert/null texture and
+    // get a graphics-level error downstream.
     class ExternalTexture::Impl final : public ImplBase
     {
     public:
@@ -20,18 +27,16 @@ namespace Babylon::Plugins
 
         Graphics::TextureT Get() const
         {
-            throw std::runtime_error{"not implemented"};
+            return Graphics::TextureT{};
         }
 
     private:
         static void GetInfo(Graphics::TextureT, std::optional<Graphics::TextureFormatT>, Info&)
         {
-            throw std::runtime_error{"not implemented"};
         }
 
         void Set(Graphics::TextureT)
         {
-            throw std::runtime_error{"not implemented"};
         }
     };
 }