--- /dev/null
+<?php
+
+namespace Drupal\block_content\Plugin\migrate\source\d6;
+
+use Drupal\migrate_drupal\Plugin\migrate\source\DrupalSqlBase;
+
+/**
+ * Drupal 6 block source from database.
+ *
+ * @MigrateSource(
+ * id = "d6_box"
+ * )
+ */
+class Box extends DrupalSqlBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function query() {
+ $query = $this->select('boxes', 'b')
+ ->fields('b', ['bid', 'body', 'info', 'format']);
+ $query->orderBy('b.bid');
+
+ return $query;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function fields() {
+ return [
+ 'bid' => $this->t('The numeric identifier of the block/box'),
+ 'body' => $this->t('The block/box content'),
+ 'info' => $this->t('Admin title of the block/box.'),
+ 'format' => $this->t('Input format of the custom block/box content.'),
+ ];
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getIds() {
+ $ids['bid']['type'] = 'integer';
+ return $ids;
+ }
+
+}