diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 117bdbf5407..30c6d7f71a4 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -5047,10 +5047,16 @@
             "url": "/_mozilla/mozilla/variadic-interface.html"
           }
         ],
-        "mozilla/webgl_context_creation_error.html": [
+        "mozilla/webgl/context_creation_error.html": [
           {
-            "path": "mozilla/webgl_context_creation_error.html",
-            "url": "/_mozilla/mozilla/webgl_context_creation_error.html"
+            "path": "mozilla/webgl/context_creation_error.html",
+            "url": "/_mozilla/mozilla/webgl/context_creation_error.html"
+          }
+        ],
+        "mozilla/webgl/get_supported_extensions.html": [
+          {
+            "path": "mozilla/webgl/get_supported_extensions.html",
+            "url": "/_mozilla/mozilla/webgl/get_supported_extensions.html"
           }
         ],
         "mozilla/websocket_connection_fail.html": [
diff --git a/tests/wpt/mozilla/tests/mozilla/webgl_context_creation_error.html b/tests/wpt/mozilla/tests/mozilla/webgl/context_creation_error.html
similarity index 100%
rename from tests/wpt/mozilla/tests/mozilla/webgl_context_creation_error.html
rename to tests/wpt/mozilla/tests/mozilla/webgl/context_creation_error.html
diff --git a/tests/wpt/mozilla/tests/mozilla/webgl/get_supported_extensions.html b/tests/wpt/mozilla/tests/mozilla/webgl/get_supported_extensions.html
new file mode 100644
index 00000000000..691535db476
--- /dev/null
+++ b/tests/wpt/mozilla/tests/mozilla/webgl/get_supported_extensions.html
@@ -0,0 +1,20 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>WebGLContextEvent getSupportedExtensions test</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+test(function() {
+  var gl = document.createElement("canvas").getContext("webgl");
+
+  if (!gl)
+    return;
+
+  var extensions = gl.getSupportedExtensions();
+  assert_true(Array.isArray(extensions), "getSupportedExtensions should return an array");
+
+  for (var i = 0; i < extensions.length; ++i)
+    assert_true(typeof(extensions[i]) === "string", "Extensions should be strings, got " + typeof(extensions[i]));
+
+});
+</script>
