What is Krumo, and when enabled, what does it do for a CiviCRM site?
Krumo is part of the Drupal Devel module. If you want to print out debugging statements in Drupal, you can put this line in your code:
It will print out the variable info with much more nicely-formatted HTML than just print_r() or similar.
In CiviCRM, I don't use this - I prefer
There are variations on that available here: http://wiki.civicrm.org/confluence/pages/viewpage.action?pageId=33129619
Though this page seems to suggest that maybe the variations are deprecated.