Issue #2763539 by felribeiro: Bug in doxygen for adding headers to a response via render #attached

core/lib/Drupal/Core/Render/AttachmentsResponseProcessorInterface.php

@@ -25,7 +25,7 @@ interface AttachmentsResponseProcessorInterface {
    * $build['#attached']['library'][] = [
    *   'library' => ['core/jquery']
    * ];
-   * $build['#attached']['http_header'][] = [
+   * $build['#attached']['http_header'] = [
    *   ['Content-Type', 'application/rss+xml; charset=utf-8'],
    * ];
    * @endcode