diff --git a/index.html b/index.html
index 1afc587..510cfe3 100755
--- a/index.html
+++ b/index.html
@@ -917,7 +917,7 @@ <h5>Media Zero Timecode</h5>
               zero seconds on the media timeline.</p>
             <p>A <a>Legacy Metadata</a> MAY contain zero or one <a>Media Zero Timecode</a> objects.</p>
             <p>The <a>Media Zero Timecode</a> object is represented in a <a>DAPT Document</a> by
-              a <code>&lt;daptm:mediaZeroTimecode&gt;</code> element present at the path
+              a <code>&lt;</code><dfn><code>daptm:mediaZeroTimecode</code></dfn><code>&gt;</code> element present at the path
               <code>/tt/head/metadata/daptm:legacy/daptm:mediaZeroTimecode</code>,
               with the following constraints:</p>
             <ul>
@@ -3237,6 +3237,13 @@ <h4>Disposition of Features and Extensions</h4>
               This is the profile expression of <a href="#ttp-contentprofiles"></a>.
             </td>
           </tr>
+          <tr>
+            <td><a href="#mediazerotimecode"><code>#mediaZeroTimecode</code></a></td>
+            <td><span class="permitted label">permitted</span></td>
+            <td>
+              This is the profile expression of <a href="#media-zero-timecode"></a>.
+            </td>
+          </tr>
           <tr>
             <td><a href="#onscreen"><code>#onScreen</code></a></td>
             <td><span class="permitted label">permitted</span></td>
@@ -3400,6 +3407,15 @@ <h3>#contentProfiles-root</h3>
       </aside>
       </section>
 
+      <section>
+        <h3>#mediaZeroTimecode</h3>
+        <p>A <a>transformation processor</a> supports the <code>#mediaZeroTimecode</code> extension if
+          it recognizes and is capable of transforming values of the
+          <code>&lt;</code><a><code>daptm:mediaZeroTimecode</code></a><code>&gt;</code> element.</p>
+  
+        <p>No <a>presentation processor</a> behaviour is defined for the <code>#mediaZeroTimecode</code> extension.</p>
+      </section>
+
       <section>
         <h3>#onScreen</h3>
         <p>A <a>transformation processor</a> supports the <code>#onScreen</code> extension if
diff --git a/profiles/dapt-content-profile.xml b/profiles/dapt-content-profile.xml
index 4c9ff64..bb36af2 100644
--- a/profiles/dapt-content-profile.xml
+++ b/profiles/dapt-content-profile.xml
@@ -90,6 +90,7 @@
     <extension value="required">#xmlLang-root</extension>
     <!-- optional (voluntary) extension support -->
     <extension value="optional">#agent</extension>
+    <extension value="optional">#mediaZeroTimecode</extension>
     <extension value="optional">#onScreen</extension>
     <extension value="optional">#scriptEventMapping</extension>
     <extension value="optional">#textLanguageSource</extension>
diff --git a/profiles/dapt-processor-profile.xml b/profiles/dapt-processor-profile.xml
index 4fd8f9c..d6ef56f 100644
--- a/profiles/dapt-processor-profile.xml
+++ b/profiles/dapt-processor-profile.xml
@@ -84,6 +84,7 @@
     <!-- required (mandatory) extension support -->
     <extension value="required">#agent</extension>
     <extension value="required">#contentProfiles-root</extension>
+    <extension value="required">#mediaZeroTimecode</extension>
     <extension value="required">#onScreen</extension>
     <extension value="required">#represents-root</extension>
     <extension value="required">#scriptType-root</extension>