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diff --git a/dom/canvas/test/webgl-conf/checkout/conformance2/wasm/readpixels-16gb-wasm-memory.html b/dom/canvas/test/webgl-conf/checkout/conformance2/wasm/readpixels-16gb-wasm-memory.html
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+++ b/dom/canvas/test/webgl-conf/checkout/conformance2/wasm/readpixels-16gb-wasm-memory.html
@@ -0,0 +1,51 @@
+<!--
+Copyright (c) 2023 The Khronos Group Inc.
+Use of this source code is governed by an MIT-style license that can be
+found in the LICENSE.txt file.
+-->
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>gl.readPixels() test to Wasm Memory 16GB in size.</title>
+<link rel="stylesheet" href="../../resources/js-test-style.css"/>
+<script src="../../js/js-test-pre.js"></script>
+<script src="../../js/webgl-test-utils.js"> </script>
+</head>
+<body>
+<canvas id="canvas" width="2" height="2" style="width: 40px; height: 40px;"></canvas>
+<div id="description"></div>
+<div id="console"></div>
+<script>
+"use strict";
+description(document.title);
+debug("");
+debug("Tests that gl.readPixels() can be called on WebAssembly Memory of 16GB in size.");
+debug("");
+let wtu = WebGLTestUtils;
+let gl = wtu.create3DContext("canvas", undefined, 2);
+
+const PAGE = 65536;
+const SIZE = 16*1024*1024*1024;
+let view = new Uint8Array(new WebAssembly.Memory({ index: 'i64', initial: SIZE/PAGE }).buffer);
+
+// Clear the canvas to a specific color
+const expectedColor = [42, 84, 128, 255];
+gl.clearColor(expectedColor[0]/255.0, expectedColor[1]/255.0, expectedColor[2]/255.0, expectedColor[3]/255.0);
+gl.clear(gl.COLOR_BUFFER_BIT);
+
+// Test that gl.readPixels() can be called with a high offset to Memory
+const offset = SIZE - 4;
+view.set([0,0,0,0], offset); // For good measure, clear data at offset before reading
+gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, view, offset);
+wtu.glErrorShouldBe(gl, gl.NO_ERROR);
+let obtainedColor = view.subarray(offset, offset+4);
+shouldBe('obtainedColor[0]', 'expectedColor[0]');
+shouldBe('obtainedColor[1]', 'expectedColor[1]');
+shouldBe('obtainedColor[2]', 'expectedColor[2]');
+shouldBe('obtainedColor[3]', 'expectedColor[3]');
+var successfullyParsed = true;
+</script>
+<script src="../../js/js-test-post.js"></script>
+</body>
+</html>