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diff --git a/testing/web-platform/tests/css/geometry/DOMMatrix-a-f-alias.html b/testing/web-platform/tests/css/geometry/DOMMatrix-a-f-alias.html
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+++ b/testing/web-platform/tests/css/geometry/DOMMatrix-a-f-alias.html
@@ -0,0 +1,57 @@
+<!DOCTYPE html>
+<title>Geometry Interfaces: DOMMatrix and DOMMatrixReadOnly a-f alias attributes</title>
+<link rel="help" href="https://drafts.fxtf.org/geometry/#DOMMatrix">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+function defineThrowingGetter(object, attribute) {
+   Object.defineProperty(object, attribute, {
+     get: () => assert_unreached(`getter for ${attribute}`)
+   });
+}
+
+function defineThrowingSetter(object, attribute) {
+   Object.defineProperty(object, attribute, {
+     set: () => assert_unreached(`setter for ${attribute}`)
+   });
+}
+
+["DOMMatrix", "DOMMatrixReadOnly"].forEach((constr) => {
+  [
+    ["a", "m11"],
+    ["b", "m12"],
+    ["c", "m21"],
+    ["d", "m22"],
+    ["e", "m41"],
+    ["f", "m42"],
+  ].forEach(([aliasAttribute, mAttribute]) => {
+     test(() => {
+       const matrix = new self[constr]([0, 0, 0, 0, 0, 0]);
+       defineThrowingGetter(matrix, mAttribute);
+       assert_equals(matrix[aliasAttribute], 0);
+     }, `${constr} getting ${aliasAttribute} with throwing getter for ${mAttribute}`);
+
+     test(() => {
+       const matrix = new self[constr]([0, 0, 0, 0, 0, 0]);
+       defineThrowingGetter(matrix, aliasAttribute);
+       assert_equals(matrix[mAttribute], 0);
+     }, `${constr} getting ${mAttribute} with throwing getter for ${aliasAttribute}`);
+
+     if (constr === "DOMMatrix") {
+       test(() => {
+         const matrix = new self[constr]([0, 0, 0, 0, 0, 0]);
+         defineThrowingSetter(matrix, mAttribute);
+         matrix[aliasAttribute] = 1;
+         assert_equals(matrix[aliasAttribute], 1);
+       }, `${constr} setting ${aliasAttribute} with throwing setter for ${mAttribute}`);
+
+       test(() => {
+         const matrix = new self[constr]([0, 0, 0, 0, 0, 0]);
+         defineThrowingSetter(matrix, aliasAttribute);
+         matrix[mAttribute] = 1;
+         assert_equals(matrix[mAttribute], 1);
+       }, `${constr} setting ${mAttribute} with throwing setter for ${aliasAttribute}`);
+     }
+   });
+});
+</script>