gistfile1.txt

  /**
   * Returns the plugin category that this display requires.
   *
   * This can be used for filtering views plugins. E.g. If a plugin category of
   * 'foo' is specified, only plugins with no 'types' declared or 'types'
   * containing 'foo'. If you have a type of bar, this plugin will not be used.
   * This is applicable for style, row, access, cache, and exposed_form plugins.
   *
   * @return string
   *   The required category type. Defaults to 'normal'.
   *
   * @see views_fetch_plugin_names()
   */