Index: source
===================================================================
--- source	(revision 1477)
+++ source	(revision 1478)
@@ -9347,10 +9347,11 @@
   </dl>
 
   <p>The <code>abbr</code> element represents an abbreviation or
-  acronym, with its expansion. The <dfn
-  title="attr-abbr-title"><code>title</code></dfn> attribute must be
-  used to provide an expansion of the abbreviation. The attribute must
-  only contain an expansion of the abbreviation.</p>
+  acronym, optionally with its expansion. The <dfn
+  title="attr-abbr-title"><code>title</code></dfn> attribute may be
+  used to provide an expansion of the abbreviation. The attribute, if
+  specified, must contain an expansion of the abbreviation, and
+  nothing else.</p>
 
   <div class="example">
    <p>The paragraph below contains an abbreviation marked up with the
@@ -9379,6 +9380,15 @@
 have much representation from Asia.&lt;/p></pre>
   </div>
 
+  <div class="example">
+   <p>This paragraph marks up an abbreviation without giving an
+   expansion, possibly as a hook to apply styles for abbreviations
+   (e.g. smallcaps).</p>
+   <pre>&lt;p>Philip` and Dashiva both denied that they were going to
+get the issue counts from past revisions of the specification to
+backfill the &lt;abbr>WHATWG&lt;/abbr> issue graph.&lt;/p></pre>
+  </div>
+
 
   <h4>The <dfn><code>time</code></dfn> element</h4>