Add content to wordpress edit.php page

The action load-edit.php is not needed. The answer on Stack Overflow is based on this WPSE answer: How do you create a custom edit.php / edit pages page that uses pre_get_posts, that’s why it was encapsulated inside load-PAGE action.

On the screen edit.php we don’t have any action hooks to insert content. We can only use the filter views_edit-POST_TYPE to do something there. With jQuery we can adjust the position on screen.

add_filter( 'views_edit-POST_TYPE', function($views){
    echo '<h2 style="display:none;" id="my-element">My Custom HTML</h2>';
    echo "<script>
        jQuery(document).ready(function($){
            $('#my-element').detach().insertBefore('#ajax-response').fadeIn();
        });
        </script>";
    return $views;
});

Without jQuery it prints on position 1, and on position 2 using it.