diff --git a/source b/source
index 3ed0c5218ff..beb2f358027 100644
--- a/source
+++ b/source
@@ -4610,6 +4610,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li><dfn data-x="tt-scripturlstring" data-x-href="https://w3c.github.io/trusted-types/dist/spec/#typedefdef-scripturlstring"><code>ScriptURLString</code></dfn></li>
      <li><dfn data-x="tt-trustedhtml" data-x-href="https://w3c.github.io/trusted-types/dist/spec/#trustedhtml"><code>TrustedHTML</code></dfn></li>
      <li><dfn data-x="tt-trustedhtml-data" data-x-href="https://w3c.github.io/trusted-types/dist/spec/#trustedhtml-data">data</dfn></li>
+     <li><dfn data-x="tt-trustedscript" data-x-href="https://w3c.github.io/trusted-types/dist/spec/#trusted-script"><code>TrustedScript</code></dfn></li>
      <li><dfn data-x="tt-getcompliantstring" data-x-href="https://w3c.github.io/trusted-types/dist/spec/#get-trusted-type-compliant-string-algorithm">Get Trusted Type compliant string</dfn></li>
     </ul>
    </dd>
@@ -111834,7 +111835,7 @@ interface mixin <dfn interface>WindowEventHandlers</dfn> {
   interface mixin <span>WindowOrWorkerGlobalScope</span> { &hellip; };</code> along with an
   appropriate reference.</p>
 
-  <pre><code class="idl">typedef (DOMString or <span data-x="idl-Function">Function</span>) <dfn typedef>TimerHandler</dfn>;
+  <pre><code class="idl">typedef (DOMString or <span data-x="idl-Function">Function</span> or <span data-x="tt-trustedscript">TrustedScript</span>) <dfn typedef>TimerHandler</dfn>;
 
 interface mixin <dfn interface>WindowOrWorkerGlobalScope</dfn> {
   [Replaceable] readonly attribute USVString <span data-x="dom-origin">origin</span>;
@@ -113224,9 +113225,10 @@ enum <dfn enum>DOMParserSupportedType</dfn> {
 
   <p>The <!--en-GB--><dfn id="timer-initialisation-steps">timer initialization steps</dfn>, given a
   <code>WindowOrWorkerGlobalScope</code> <var>global</var>, a string or <code
-  data-x="idl-Function">Function</code> <var>handler</var>, a number <var>timeout</var>, a list
-  <var>arguments</var>, a boolean <var>repeat</var>, and optionally (and only if <var>repeat</var>
-  is true) a number <var>previousId</var>, are:</p>
+  data-x="idl-Function">Function</code> or <code data-x="tt-trustedscript">TrustedScript</code>
+  <var>handler</var>, a number <var>timeout</var>, a list <var>arguments</var>, a boolean
+  <var>repeat</var>, and optionally (and only if <var>repeat</var> is true) a number
+  <var>previousId</var>, are:</p>
 
   <ol>
    <li><p>Let <var>thisArg</var> be <var>global</var> if that is a <code>WorkerGlobalScope</code>
@@ -113282,6 +113284,28 @@ enum <dfn enum>DOMParserSupportedType</dfn> {
       <p>Otherwise:</p>
 
       <ol>
+       <li>
+        <p>If <var>previousId</var> was not given:</p>
+
+        <ol>
+         <li><p>Let <var>globalName</var> be "<code data-x="">Window</code>" if <span>this</span>'s
+         <span>relevant global object</span> is a <code>Window</code> object; "<code
+         data-x="">Worker</code>" otherwise.</p></li>
+
+         <li><p>Let <var>methodName</var> be "<code data-x="">setInterval</code>" if
+         <var>repeat</var> is true; "<code data-x="">setTimeout</code>" otherwise.</p></li>
+
+         <li><p>Let <var>sink</var> be a concatenation of <var>globalName</var>, U+0020 SPACE, and
+         <var>methodName</var>.</p></li>
+
+         <li><p>Set <var>handler</var> to the result of invoking the <span
+         data-x="tt-getcompliantstring">Get Trusted Type compliant string</span> algorithm with
+         <code data-x="tt-trustedscript">TrustedScript</code>, <span>this</span>'s <span>relevant
+         global object</span>, <var>handler</var>, <var>sink</var>, and "<code
+         data-x="">script</code>".</p></li>
+        </ol>
+       </li>
+
        <li><p><span>Assert</span>: <var>handler</var> is a string.</p></li>
 
        <li><p>Perform <span