--- /dev/null
+<?php
+
+namespace Drupal\system\Plugin\migrate\source\d7;
+
+use Drupal\migrate_drupal\Plugin\migrate\source\VariableMultiRow;
+
+/**
+ * Drupal 7 system source from database.
+ *
+ * @MigrateSource(
+ * id = "d7_theme_settings",
+ * source_provider = "system"
+ * )
+ */
+class ThemeSettings extends VariableMultiRow {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function query() {
+ return $this->select('variable', 'v')
+ ->fields('v', ['name', 'value'])
+ ->condition('name', 'theme_%_settings', 'LIKE');
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function fields() {
+ return [
+ 'name' => $this->t('Theme settings variable for a theme.'),
+ 'value' => $this->t('The theme settings variable value.'),
+ ];
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getIds() {
+ $ids['name']['type'] = 'string';
+ return $ids;
+ }
+
+}