Tools/TestWebKitAPI/Tests/WebKitCocoa/web-authentication-get-assertion.html

<input type="text" id="input">
<script>
    if (window.internals)
        internals.withUserGesture(() => { input.focus(); });

    const options = {
        publicKey: {
            challenge: new Uint8Array(16),
            timeout: 1
        }
    };

    navigator.credentials.get(options);
</script>