add_filter('manage_edit-section_columns', function ($columns) {
  $columns = array(
    'cb' => 'cb',
    'title' => 'Заголовок',
    'priority' => 'Приоритет'
  );

  return $columns;
}, 4);

add_filter('manage_section_posts_custom_column', function ($column_name, $post_id) {
  if ($column_name == 'priority') {
    echo get_post_meta($post_id, 'priority', true);
  }
}, 5, 2);