diff -urN api/api.css /srv/www/htdocs/6/sites/all/modules/api/api.css
--- api/api.css	2009-01-28 22:05:03.000000000 +0100
+++ /srv/www/htdocs/6/sites/all/modules/api/api.css	2009-08-05 02:27:21.000000000 +0200
@@ -104,3 +104,10 @@
 #api-search-form #autocomplete {
   width: 250px !important;
 }
+
+#api-warning {
+  margin: 1em;
+  padding: 1em;
+  border: 1px solid;
+  font-size: 0.9em;
+}
diff -urN api/api.module /srv/www/htdocs/6/sites/all/modules/api/api.module
--- api/api.module	2009-08-01 08:59:04.000000000 +0200
+++ /srv/www/htdocs/6/sites/all/modules/api/api.module	2009-08-05 02:30:34.000000000 +0200
@@ -560,6 +560,12 @@
       ),
       'template' => 'templates/api-group-page'
     ),
+    'api_default_page' => array(
+      'arguments' => array(
+        'branch' => NULL,
+      ),
+      'template' => 'templates/api-default-page'
+    ),
   );
 }
 
@@ -965,7 +971,7 @@
     return api_link_documentation($branch->documentation, $branch_name);
   }
   else {
-    return t('A main page for this branch has not been indexed. A documentation comment with <code>@mainpage {title}</code> needs to exist, or has not been indexed yet. For Drupal core, this is available in the <a href="http://cvs.drupal.org/viewvc.py/drupal/contributions/docs/developer/">developer documentation</a> in the contributions repository.');
+    return theme('api_default_page', $branch_name);
   }
 }
 
diff -urN api/templates/api-default-page.tpl.php /srv/www/htdocs/6/sites/all/modules/api/templates/api-default-page.tpl.php
--- api/templates/api-default-page.tpl.php	1970-01-01 01:00:00.000000000 +0100
+++ /srv/www/htdocs/6/sites/all/modules/api/templates/api-default-page.tpl.php	2009-08-05 02:28:39.000000000 +0200
@@ -0,0 +1,13 @@
+<?php if (!empty($branch)) { ?>
+<h3><?php print l('Topics', "api/groups/$branch") ?></h3>
+<?php print api_page_listing($branch, 'group') ?>
+<h3><?php print l('Files', "api/files/$branch") ?></h3>
+<h3><?php print l('Globals', "api/globals/$branch") ?></h3>
+<h3><?php print l('Constants', "api/constants/$branch") ?></h3>
+<h3><?php print l('Functions', "api/functions/$branch") ?></h3>
+<h3><?php print l('API Search', "api/search/$branch") ?></h3>
+<?php } ?>
+
+<p id="api-warning">
+<?php print t('A main page for this branch has not been indexed. A documentation comment with <code>@mainpage {title}</code> needs to exist, or has not been indexed yet. For Drupal core, this is available in the <a href="http://cvs.drupal.org/viewvc.py/drupal/contributions/docs/developer/">developer documentation</a> in the contributions repository.') ?>
+</p>