let holder copy issuer

Signed-off-by: Brent Zundel <[email protected]>

index.html

@@ -1936,8 +1936,13 @@ <h3>Presentations</h3>
           </dd>
           <dt><var>holder</var></dt>
           <dd>
-The <a>verifiable presentation</a> MAY include a <code>holder</code> <a>property</a>. If present, the value
-MUST be a <a>URL</a> for the entity that is generating the <a>verifiable presentation</a>.
+The <a>verifiable presentation</a> MAY include a <code>holder</code>
+<a>property</a>. If present, the value MUST be either a <a>URL</a> or an object
+containing an <code>id</code> <a>property</a>. It is RECOMMENDED that the
+<a>URL</a> in the <code>holder</code> or its <code>id</code> be one which, if
+dereferenced, results in a document containing machine-readable information
+about the <a>holder</a> that can be used to <a>verify</a> the information
+expressed in the <a>verifiable presentation</a>.
           </dd>
           <dt><var>proof</var></dt>
           <dd>