The block is handling its own caching in its hook_block_view().

This setting is useful when time based expiration is needed or a site uses a node access which invalidates standard block cache.

Related topics

2 uses of DRUPAL_CACHE_CUSTOM
forum_block_info in modules/forum/forum.module
Implements hook_block_info().
_block_get_cache_id in modules/block/block.module
Assemble the cache_id to use for a given block.

File

includes/common.inc, line 135
Common functions that many Drupal modules will need to reference.

Code

define('DRUPAL_CACHE_CUSTOM', -2)