Ported the commits from issue w3c#560. Next, find other commits

that this needs for completeness (attribute defs, IDL, etc.)

sections/semantics-embedded-content.include

@@ -1217,7 +1217,8 @@
     &#x231B; If the element uses <code>srcset</code> or <code>picture</code>, set
     <var>request</var>'s <a>initiator</a> to "<code>imageset</code>".
 
-    &#x231B; Set <var>request</var>'s <a>same-origin data-URL flag</a>.
+    &#x231B; Set <var>request</var>'s <a>referrer policy</a> to the current state of the
+    element's <code>referrerpolicy</code> attribute.
 
     &#x231B; <a>Fetch</a> <var>request</var>. Let this
     instance of the <a>fetching</a> algorithm be associated with
@@ -2091,6 +2092,9 @@
       <li>Set <var>request</var>'s <a>client</a> to
       <var>client</var>, <a for="request">type</a> to "<code>image</code>", and set <var>request</var>'s <a>synchronous flag</a>.</li>
 
+      <li>Set <var>request</var>'s <a>referrer policy</a> to the current state of the
+      element's <code>referrerpolicy</code> attribute.</li>
+
       <li>Let <var>response</var> be the result of <a>fetching</a> <var>request</var>.</li>
 
       <li>If <var>response</var>'s unsafe response is a network error or