diff --git a/core/modules/user/templates/username.html.twig b/core/modules/user/templates/username.html.twig
index 6c1fccbfff12..10c7a6b0694e 100644
--- a/core/modules/user/templates/username.html.twig
+++ b/core/modules/user/templates/username.html.twig
@@ -5,10 +5,16 @@
  *
  * Available variables:
  * - account: The full account information for the user.
- * - name: The user's name, sanitized.
+ * - uid: The user ID, or zero if not a user. As used in anonymous comments.
+ * - name: The user's name, sanitized, and optionally truncated.
+ * - name_raw: The user's name, un-truncated.
+ * - truncated: Whether the user's name was truncated.
  * - extra: Additional text to append to the user's name, sanitized.
+ * - profile_access: Whether the current user has permission to access this
+     users profile page.
  * - link_path: The path or URL of the user's profile page, home page,
  *   or other desired page to link to for more information about the user.
+ * - homepage: (optional) The home page of the account, only set for non users.
  * - link_options: Options to set on the \Drupal\Core\Url object if linking the
  *   user's name to the user's page.
  * - attributes: HTML attributes for the containing element.
diff --git a/core/themes/classy/templates/user/username.html.twig b/core/themes/classy/templates/user/username.html.twig
index 5a6c3a55209a..df694dff6980 100644
--- a/core/themes/classy/templates/user/username.html.twig
+++ b/core/themes/classy/templates/user/username.html.twig
@@ -5,10 +5,16 @@
  *
  * Available variables:
  * - account: The full account information for the user.
- * - name: The user's name, sanitized.
+ * - uid: The user ID, or zero if not a user. As used in anonymous comments.
+ * - name: The user's name, sanitized, and optionally truncated.
+ * - name_raw: The user's name, un-truncated.
+ * - truncated: Whether the user's name was truncated.
  * - extra: Additional text to append to the user's name, sanitized.
+ * - profile_access: Whether the current user has permission to access this
+     users profile page.
  * - link_path: The path or URL of the user's profile page, home page,
  *   or other desired page to link to for more information about the user.
+ * - homepage: (optional) The home page of the account, only set for non users.
  * - link_options: Options to set on the \Drupal\Core\Url object if linking the
  *   user's name to the user's page.
  * - attributes: HTML attributes for the containing element.
diff --git a/core/themes/stable/templates/user/username.html.twig b/core/themes/stable/templates/user/username.html.twig
index 480225f15d12..7f62f9b450d0 100644
--- a/core/themes/stable/templates/user/username.html.twig
+++ b/core/themes/stable/templates/user/username.html.twig
@@ -5,10 +5,16 @@
  *
  * Available variables:
  * - account: The full account information for the user.
- * - name: The user's name, sanitized.
+ * - uid: The user ID, or zero if not a user. As used in anonymous comments.
+ * - name: The user's name, sanitized, and optionally truncated.
+ * - name_raw: The user's name, un-truncated.
+ * - truncated: Whether the user's name was truncated.
  * - extra: Additional text to append to the user's name, sanitized.
+ * - profile_access: Whether the current user has permission to access this
+     users profile page.
  * - link_path: The path or URL of the user's profile page, home page,
  *   or other desired page to link to for more information about the user.
+ * - homepage: (optional) The home page of the account, only set for non users.
  * - link_options: Options to set on the \Drupal\Core\Url object if linking the
  *   user's name to the user's page.
  * - attributes: HTML attributes for the containing element.