diff --git a/core/modules/system/src/Tests/Entity/EntityValidationTest.php b/core/modules/system/src/Tests/Entity/EntityValidationTest.php
index ef42036..6061acb 100644
--- a/core/modules/system/src/Tests/Entity/EntityValidationTest.php
+++ b/core/modules/system/src/Tests/Entity/EntityValidationTest.php
@@ -116,6 +116,7 @@ protected function checkValidation($entity_type) {
     // This should fail on AllowedValues and Length constraints.
     $this->assertEqual($violations->count(), 2, 'Validation failed.');
     $this->assertEqual($violations[0]->getMessage(), t('This value is too long. It should have %limit characters or less.', array('%limit' => '12')));
+    $this->assertEqual($violations[1]->getMessage(), t('The value you selected is not a valid choice.'));
 
     $test_entity = clone $entity;
     $test_entity->type->value = NULL;
diff --git a/core/modules/user/src/AccountForm.php b/core/modules/user/src/AccountForm.php
index ab32c82..033731f 100644
--- a/core/modules/user/src/AccountForm.php
+++ b/core/modules/user/src/AccountForm.php
@@ -364,6 +364,8 @@ public function buildEntity(array $form, FormStateInterface $form_state) {
     /** @var \Drupal\user\UserInterface $account */
     $account = parent::buildEntity($form, $form_state);
 
+    // Take care of mapping signature form element values as their structure
+    // does not directly match the field structure.
     $signature = $form_state->getValue('signature');
     $account->setSignature($signature['value']);
     $account->setSignatureFormat($signature['format']);
@@ -386,7 +388,8 @@ public function validate(array $form, FormStateInterface $form_state) {
     /** @var \Drupal\user\UserInterface $account */
     $account = $this->buildEntity($form, $form_state);
     // Customly trigger validation of manually added fields and add in
-    // violations.
+    // violations. This is necessary as entity form displays only invoke entity
+    // validation for fields contained in the display.
     $field_names = array(
       'name',
       'mail',
diff --git a/core/modules/user/src/Entity/User.php b/core/modules/user/src/Entity/User.php
index 8af4db2..8be2e5e 100644
--- a/core/modules/user/src/Entity/User.php
+++ b/core/modules/user/src/Entity/User.php
@@ -598,6 +598,7 @@ protected function getRoleStorage() {
    * Defines allowed signature formats for the field's AllowedValues constraint.
    *
    * @return string[]
+   *   The allowed values.
    */
   public static function getAllowedSignatureFormats() {
     if (\Drupal::moduleHandler()->moduleExists('filter')) {
@@ -611,6 +612,7 @@ public static function getAllowedSignatureFormats() {
    * Defines allowed timezones for the field's AllowedValues constraint.
    *
    * @return string[]
+   *   The allowed values.
    */
   public static function getAllowedTimezones() {
     return array_keys(system_time_zones());
@@ -620,6 +622,7 @@ public static function getAllowedTimezones() {
    * Defines allowed configurable language codes for AllowedValues constraints.
    *
    * @return string[]
+   *   The allowed values.
    */
   public static function getAllowedConfigurableLanguageCodes() {
     return array_keys(\Drupal::languageManager()->getLanguages(LanguageInterface::STATE_CONFIGURABLE));