popsu-d7/sites/all/modules/mb/mb_comment/mb_comment.install

<?php

/**
 * @file
 * Installs, updates, and uninstalls More Buttons Comment.
 */

/**
 * Implements hook_uninstall().
 */
function mb_comment_uninstall() {
  // Remove variables.
  $node_types = array_keys(node_type_get_types());
  foreach ($node_types as $type) {
    variable_del('mb_comment_cancel_' . $type);
  }
}