diff --git a/index.html b/index.html
index c819164..7fd73f8 100644
--- a/index.html
+++ b/index.html
@@ -846,6 +846,12 @@ <h3>
           represented by a <a>Promise</a> that resolves with the
           <a>presentation controllers monitor</a>.
         </p>
+        <p>
+          In a <a>controlling browsing context</a>, the <dfn>default
+          presentation request</dfn>, which is initially set to
+          <code>null</code>, represents the request to use when the user wishes
+          to initiate a <a>presentation connection</a> from the browser.
+        </p>
       </section>
       <section>
         <h3>
@@ -870,6 +876,10 @@ <h3>
           <h4>
             Controlling user agent
           </h4>
+          <p>
+            <a data-lt="controlling user agent">Controlling user agents</a>
+            MUST implement the following partial interface:
+          </p>
           <pre class="idl idl-controlling-ua">
             partial interface Presentation {
               attribute PresentationRequest? defaultRequest;
@@ -877,26 +887,10 @@ <h4>
           
 </pre>
           <p>
-            In a <a>controlling user agent</a>, the <dfn for=
-            "Presentation"><code>defaultRequest</code></dfn> attribute MUST
-            return the <a>default presentation request</a> if any,
-            <code>null</code> otherwise. In a <a>receiving browsing
-            context</a>, it MUST return <code>null</code>.
-          </p>
-          <p>
-            If set by the <a>controller</a>, the value of the <a for=
-            "Presentation">defaultRequest</a> attribute SHOULD be used by the
-            <a>controlling user agent</a> as the <dfn>default presentation
-            request</dfn> for that <a>controlling browsing context</a>. If the
-            the document object's <a>active sandboxing flag set</a> has the
-            <a>sandboxed presentation browsing context flag</a> set, the
-            <a>controlling user agent</a> SHOULD consider the <a>default
-            presentation request</a> for that browsing context to be
-            <code>null</code>. When the <a>controlling user agent</a> wishes to
-            initiate a <a>PresentationConnection</a> on the behalf of that
-            browsing context, it MUST <a>start a presentation</a> using the
-            <a>default presentation request</a> for the <a>controller</a> (as
-            if the controller had called <code>defaultRequest.start()</code>).
+            The <dfn for="Presentation"><code>defaultRequest</code></dfn>
+            attribute MUST return the <a>default presentation request</a> if
+            any, <code>null</code> otherwise. On setting, the <a>default
+            presentation request</a> MUST be set to the new value.
           </p>
           <p>
             The <a>controlling user agent</a> SHOULD initiate presentation
@@ -904,9 +898,26 @@ <h4>
             has expressed an intention to do so via a user gesture, for example
             by clicking a button in the browser.
           </p>
+          <p>
+            To initiate presentation using the <a>default presentation
+            request</a>, the <a>controlling user agent</a> MUST <a>start a
+            presentation</a> using the <a>default presentation request</a> (as
+            if the controller had called <code>defaultRequest.start()</code>),
+            skipping the first step of that algorithm.
+          </p>
+          <div class="note">
+            Subsequent security steps of the <a>start a presentation</a>
+            algorithm apply. For instance, the request will fail if the
+            document object's <a>active sandboxing flag set</a> has the
+            <a>sandboxed presentation browsing context flag</a> set.
+          </div>
+          <p>
+            Support for the initiation of a <a>presentation connection</a> from
+            the browser is OPTIONAL.
+          </p>
           <div class="note">
             If a <a>controlling user agent</a> does not support initiation of a
-            <a>presentation connection</a> from the browser chrome, setting
+            <a>presentation connection</a> from the browser, setting
             <code>defaultRequest</code> will have no effect.
           </div>
           <div class="note">
@@ -928,6 +939,10 @@ <h4>
           <h4>
             Receiving user agent
           </h4>
+          <p>
+            <a data-lt="Receiving user agent">Receiving user agents</a> MUST
+            implement the following partial interface:
+          </p>
           <pre class="idl idl-receiving-ua">
             partial interface Presentation {
               [SameObject] readonly attribute PresentationReceiver? receiver;
@@ -935,26 +950,13 @@ <h4>
           
 </pre>
           <p>
-            In a <a>receiving user agent</a>, the <dfn for=
-            "Presentation"><code>receiver</code></dfn> attribute MUST return
-            the <a><code>PresentationReceiver</code></a> instance associated
-            with the <a>receiving browsing context</a> and created by the
-            <a>receiving user agent</a> when the <a>receiving browsing
+            The <dfn for="Presentation"><code>receiver</code></dfn> attribute
+            MUST return the <a><code>PresentationReceiver</code></a> instance
+            associated with the <a>receiving browsing context</a> and created
+            by the <a>receiving user agent</a> when the <a>receiving browsing
             context</a> is created. In any other <a>browsing context</a>, it
             MUST return <code>null</code>.
           </p>
-          <p>
-            A user agent that is a <a>receiving user agent</a> but not a
-            <a>controlling user agent</a> MUST always return <code>null</code>
-            for the <a for="Presentation">defaultRequest</a> attribute. It MUST
-            treat setting the <a for="Presentation">defaultRequest</a>
-            attribute as a no-op.
-          </p>
-          <p>
-            A user agent that is a <a>controlling user agent</a> but not a
-            <a>receiving user agent</a> MUST always return <code>null</code>
-            for the <a for="Presentation">receiver</a> attribute.
-          </p>
         </section>
       </section>
       <section>