--- /dev/null
+<?php
+
+namespace Drupal\responsive_image;
+
+use Drupal\Core\Config\Entity\ConfigEntityListBuilder;
+use Drupal\Core\Entity\EntityInterface;
+
+/**
+ * Provides a listing of responsive image styles.
+ */
+class ResponsiveImageStyleListBuilder extends ConfigEntityListBuilder {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function buildHeader() {
+ $header['label'] = t('Label');
+ $header['id'] = t('Machine name');
+ return $header + parent::buildHeader();
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function buildRow(EntityInterface $entity) {
+ $row['label'] = $entity->label();
+ $row['id'] = $entity->id();
+ return $row + parent::buildRow($entity);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getDefaultOperations(EntityInterface $entity) {
+ $operations = parent::getDefaultOperations($entity);
+ $operations['duplicate'] = [
+ 'title' => t('Duplicate'),
+ 'weight' => 15,
+ 'url' => $entity->urlInfo('duplicate-form'),
+ ];
+ return $operations;
+ }
+
+}