What is the benefit of explicitly specify `short_cache_id` in Magento Block

Question

I can see below code in the class Mage_Catalog_Block_Navigation atapp/code/core/Mage/Catalog/Block/Navigation.php

public function getCacheKeyInfo()
{
    $shortCacheId = array(
        'CATALOG_NAVIGATION',
        Mage::app()->getStore()->getId(),
        Mage::getDesign()->getPackageName(),
        Mage::getDesign()->getTheme('template'),
        Mage::getSingleton('customer/session')->getCustomerGroupId(),
        'template' => $this->getTemplate(),
        'name' => $this->getNameInLayout(),
        $this->getCurrenCategoryKey()
    );
    $cacheId = $shortCacheId;

    $shortCacheId = array_values($shortCacheId);
    $shortCacheId = implode('|', $shortCacheId);
    $shortCacheId = md5($shortCacheId);

    $cacheId['category_path'] = $this->getCurrenCategoryKey();
    $cacheId['short_cache_id'] = $shortCacheId;

    return $cacheId;
}

I know that getCacheKeyInfo() method will generate unique cache key for catalog navigation block. But my doubt is on following section

$cacheId['category_path'] = $this->getCurrenCategoryKey();
$cacheId['short_cache_id'] = $shortCacheId;

What is the benefit of setting category_path and short_cache_id in this particular method ?

Someone please enlighten me with this because it seems absurd to me.

Answer 1

In CE, there is no benefit at all.

The short_cache_id is used in EE in the Full Page Cache module to differentiate the cache id of the left navigation and the cache of the top navigation.