Meta: export "custom elements" and window.open()

Useful for w3ctag/design-principles#80.

source

@@ -66138,7 +66138,7 @@ console.log(plasticButton2.getAttribute("is")); // will output "plastic-button"<
 
   <h4 id="custom-elements-core-concepts">Core concepts</h4>
 
-  <p>A <dfn>custom element</dfn> is an element that is <span
+  <p>A <dfn export>custom element</dfn> is an element that is <span
   data-x="concept-element-custom">custom</span>. Informally, this means that its constructor and
   prototype are defined by the author, instead of by the user agent. This author-supplied
   constructor function is called the <dfn data-export="">custom element constructor</dfn>.</p>
@@ -78231,10 +78231,11 @@ callback <dfn>FrameRequestCallback</dfn> = void (<span>DOMHighResTimeStamp</span
    <li><p>Return <var>target browsing context</var>'s <code>WindowProxy</code> object.</p></li>
   </ol>
 
-  <p>The <dfn><code data-x="dom-open">open(<var>url</var>, <var>target</var>,
-  <var>features</var>)</code></dfn> method on <code>Window</code> objects provides a mechanism for
-  <span data-x="navigate">navigating</span> an existing <span>browsing context</span> or opening and
-  navigating an <span>auxiliary browsing context</span>.</p>
+  <p>The <dfn export for="Window" data-dfn-type="operation"
+  data-lt="open()|open(url, target, features)"><code data-x="dom-open">open(<var>url</var>,
+  <var>target</var>, <var>features</var>)</code></dfn> method on <code>Window</code> objects
+  provides a mechanism for <span data-x="navigate">navigating</span> an existing <span>browsing
+  context</span> or opening and navigating an <span>auxiliary browsing context</span>.</p>
 
   <p>When the method is invoked, the user agent must run the <span>window open steps</span> with
   <var>url</var>, <var>target</var>, and <var>features</var>.</p>