diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 6056350..c914a9b 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1460,6 +1460,12 @@ function drupal_pre_render_table(array $element) {
  *       )
  *     );
  *     @endcode
+ *   - footer: An array containing the table footers. Each element of the array
+ *     can be either a localized string or an associative array with the
+ *     following keys:
+ *     - "data": The localized summary information of the table column.
+ *     - Any HTML attributes, such as "colspan", to apply to the column footer
+ *       cell.
  *   - attributes: An array of HTML attributes to apply to the table tag.
  *   - caption: A localized string to use for the <caption> tag.
  *   - colgroups: An array of column groups. Each element of the array can be