diff --git a/core/modules/contact/contact.module b/core/modules/contact/contact.module
index cbdbda7..34678f7 100644
--- a/core/modules/contact/contact.module
+++ b/core/modules/contact/contact.module
@@ -169,8 +169,7 @@ function contact_config_import_change($name, $new_config, $old_config) {
     return FALSE;
   }
 
-  // @todo Make this less ugly.
-  $id = substr($name, strlen(Category::getConfigPrefix()) + 1);
+  list(, , $id) = explode('.', $name);
   $category = entity_load('contact_category', $id);
 
   $category->original = clone $category;
@@ -194,7 +193,7 @@ function contact_config_import_delete($name, $new_config, $old_config) {
     return FALSE;
   }
 
-  $id = substr($name, strlen(ConfigTest::getConfigPrefix()) + 1);
+  list(, , $id) = explode('.', $name);
   entity_delete_multiple('contact_category', array($id));
   return TRUE;
 }
diff --git a/core/modules/contact/lib/Drupal/contact/Category.php b/core/modules/contact/lib/Drupal/contact/Category.php
index dac5c33..70d2742 100644
--- a/core/modules/contact/lib/Drupal/contact/Category.php
+++ b/core/modules/contact/lib/Drupal/contact/Category.php
@@ -14,8 +14,25 @@
  */
 class Category extends ConfigurableBase {
 
+  /**
+   * The category ID.
+   *
+   * @var string
+   */
   public $id;
+
+  /**
+   * The category UUID.
+   *
+   * @var string
+   */
   public $uuid;
+
+  /**
+   * The category label.
+   *
+   * @var string
+   */
   public $label;
 
   /**
@@ -39,10 +56,4 @@ class Category extends ConfigurableBase {
    */
   public $weight = 0;
 
-  /**
-   * Implements Drupal\Core\Configurable\ConfigurableInterface::getConfigPrefix().
-   */
-  public static function getConfigPrefix() {
-    return 'contact.category';
-  }
 }