commit 314fc7c99e85b37543c77a595fa292ce8cf0ec33
Author: Florian Weber <florian@webflo.org>
Date:   Sat Jun 16 15:03:36 2012 +0200

    Issue #1616952 #10.

diff --git a/core/modules/entity/entity.api.php b/core/modules/entity/entity.api.php
index f253489..f670a6b 100644
--- a/core/modules/entity/entity.api.php
+++ b/core/modules/entity/entity.api.php
@@ -44,16 +44,15 @@
  *     uri can be constructed by passing these elements to url().
  *   - label callback: (optional) A function taking an entity and langcode as
  *     argument and returning the label of the entity. The langcode is
- *     optional. If langcode is omitted, the entity's default
- *     language is used. The entity label is the main string associated with
- *     an entity; for example, the title of a node or the subject of a
- *     comment. If there is an entity object property that defines the label,
- *     use the 'label' element of the 'entity keys' return value component to
- *     provide this information (see below). If more complex logic is needed
- *     to determine the label of an entity, you can instead specify a
- *     callback function here, which will be called to determine the entity
- *     label. See also the Drupal\entity\Entity::label() method, which
- *     implements this logic.
+ *     optional. If langcode is omitted, the entity's default language is used.
+ *     The entity label is the main string associated with an entity; for
+ *     example, the title of a node or the subject of a comment. If there is an
+ *     entity object property that defines the label, use the 'label' element
+ *     of the 'entity keys' return value component to provide this information
+ *     (see below). If more complex logic is needed to determine the label of
+ *     an entity, you can instead specify a callback function here, which will
+ *     be called to determine the entity label. See also the
+ *     Drupal\entity\Entity::label() method, which implements this logic.
  *   - fieldable: Set to TRUE if you want your entity type to be fieldable.
  *   - translation: An associative array of modules registered as field
  *     translation handlers. Array keys are the module names, array values
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index efa033a..12cb7d6 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -186,6 +186,9 @@ function user_uri($user) {
 /**
  * Entity label callback.
  *
+ * This label callback has langcode for security reasons. The username is the
+ * visual identifier for a user and needs to be consistent in all languages.
+ *
  * @param $entity_type
  *   The entity type.
  * @param $entity