Issue #3106609 by bygeoffthompson, Daniel Korte, DamienMcKenna, Maya Slatinek,...

  logic on 'Drupal 7' migrations, e.g. core upgrades.

#3102602 by jedihe, Gnanagowthaman sankar, thalles, DamienMcKenna, Berdir: Use

  DI to add services to the settings form.

#3106609 by bygeoffthompson, Daniel Korte, DamienMcKenna, Maya Slatinek,

  mrshowerman, BryanDeNijs: The Basic Description field has a maxlength of 255

  but recommends 320 or less.

Metatag 8.x-1.11, 2019-12-20

 * @MetatagTag(

 *   id = "description",

 *   label = @Translation("Description"),

 *   description = @Translation("A brief and concise summary of the page's content, preferably 320 characters or less. The description meta tag may be used by search engines to display a snippet about the page in search results."),

 *   description = @Translation("A brief and concise summary of the page's content that is a maximum of 320 characters in length. The description meta tag may be used by search engines to display a snippet about the page in search results."),

 *   name = "description",

 *   group = "basic",

 *   weight = 2,

 */

class Description extends MetaNameBase {

  /**

   * {@inheritdoc}

   */

  public function form(array $element = []) {

    $form = parent::form($element);

    $form['#maxlength'] = 320;

    return $form;

  }

}