standard install profile sets a pointless $vocabulary->help

  $vocabulary = (object) array(
    'name' => st('Tags'),
    'description' => $description,
    'machine_name' => 'tags',
    'help' => $help,

  );
  taxonomy_vocabulary_save($vocabulary);

This is later used in creating the instance:

'description' => $vocabulary->help,

But taxonomy_vocabulary_save() isn't going to do anything with it, so it's a bit misleading to put it in the vocabulary object.