Where can I find in database that page (panel) is disabled? I am using Panels module. If I go to structure -> pages menu link, I will see my pages list.

I can disable/enable those pages. But how does this work under the hood? Where is it marked in the database that some specific page is disabled?
Panel pages requires Page Manager module which comes with Ctools Module.... Below function in page_manager/page_manager.admin.inc is responsible for enable / disable action...

function page_manager_enable_page($disable, $js, $page) {
  if (!isset($_GET['token']) || !drupal_valid_token($_GET['token'], $page-&gt;task_name)) {
    return MENU_ACCESS_DENIED;
  }
  if ($page-&gt;locked) {
    if ($disable) {
      drupal_set_message(t('Unable to disable due to lock.'));
    }
    else {
      drupal_set_message(t('Unable to enable due to lock.'));
    }
  }
  else {
    if ($function = ctools_plugin_get_function($page-&gt;subtask, 'enable callback')) {
      dpm($function);
      $result = $function($page, $disable);
      menu_rebuild();

      // We want to re-cache this if it's changed so that status is properly
      // updated on the changed form.
      if (!empty($page-&gt;changed)) {
        page_manager_set_page_cache($page);
      }
    }
  }

  // For now $js is not actually in use on this.
  drupal_goto('admin/structure/pages');
}


When a panel page (Custom Created , Not default pages that comes with module) is enabled or disabled below function is called in ctools/page_manager/plugins/tasks/page.inc...

/**
 * Callback to enable/disable the page from the UI.
 */
function page_manager_page_enable(&amp;$cache, $status) {
  $page = &amp;$cache-&gt;subtask['subtask'];
  ctools_include('export');
  ctools_export_set_object_status($page, $status);

  $page-&gt;disabled = FALSE;
}


You can find panel pages details inside variable table under the variable 


  default_page_manager_pages


When Disabled

a:1:{s:15:"test_panel_page";b:1;}


When Enabled

a:0:{}


Default pages that comes with module enable / disable status also stored in variables table...