diff --git a/modules/locale/locale.api.php b/modules/locale/locale.api.php
index 2808f33..37cfed1 100644
--- a/modules/locale/locale.api.php
+++ b/modules/locale/locale.api.php
@@ -13,13 +13,28 @@
 /**
  * Allows modules to define their own text groups that can be translated.
  *
+ * Currently, the only supported $op is 'groups'. The 'groups' $op is used
+ * by the Locale module's translation interface, at
+ * admin/config/regional/translate/translate. It allows translators
+ * to filter the list of translatable strings by group.
+ *
  * @param $op
  *   Type of operation. Currently, only supports 'groups'.
+ *
+ * @return
+ *   An associative array, with machine-readable name as key and
+ *   a translated, human-readable name as value.
+ *
+ * @see http://drupal.org/node/324602
  */
 function hook_locale($op = 'groups') {
   switch ($op) {
     case 'groups':
-      return array('custom' => t('Custom'));
+      return array('myGroup' => t('My Group'));
   }
 }