6 files declare their use of ShortcutSetInterface in Zircon Profile 8

MigrateShortcutSetTest.php in core/modules/shortcut/src/Tests/Migrate/d7/MigrateShortcutSetTest.php

Contains \Drupal\shortcut\Tests\Migrate\d7\MigrateShortcutSetTest.

shortcut.module in core/modules/shortcut/shortcut.module

Allows users to manage customizable lists of shortcut links.

ShortcutController.php in core/modules/shortcut/src/Controller/ShortcutController.php

Contains \Drupal\shortcut\Controller\ShortcutController.

ShortcutSet.php in core/modules/shortcut/src/Entity/ShortcutSet.php

Contains \Drupal\shortcut\Entity\ShortcutSet.

ShortcutSetController.php in core/modules/shortcut/src/Controller/ShortcutSetController.php

Contains \Drupal\shortcut\Controller\ShortcutSetController.

ShortcutTestBase.php in core/modules/shortcut/src/Tests/ShortcutTestBase.php

Contains \Drupal\shortcut\Tests\ShortcutTestBase.