3 namespace Drupal\metatag_open_graph\Plugin\metatag\Tag;
5 use \Drupal\metatag\Plugin\metatag\Tag\MetaPropertyBase;
8 * Provides a plugin for the 'book:isbn' meta tag.
12 * label = @Translation("ISBN"),
13 * description = @Translation("The Book's ISBN"),
15 * group = "open_graph",
22 class BookISBN extends MetaPropertyBase {
23 // Nothing here yet. Just a placeholder class for a plugin.