How To Add A Hint To A Menu


I already checked some addons, but couldnt figure out how a hint text is added under the a menu in the backend.

I know that they are a language variable, but couldnt understand how they added there. I thought that this information should be in, but I not found any reference. Here is an example of hint:

For example, schema contains the following data

$schema['central']['website']['items']['comments_and_reviews'] = array(
    'attrs' => array(
    'href' => 'discussion_manager.manage',
    'position' => 601

For menu label the comments_and_reviews language variable will be used

For menu hint the comments_and_reviews_menu_description language variable will be used