Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/modules/aggregator/aggregator.theme.inc

@@ -0,0 +1,50 @@
+<?php
+
+/**
+ * @file
+ * Preprocessors and theme functions of Aggregator module.
+ */
+
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\Render\Element;
+
+/**
+ * Prepares variables for aggregator item templates.
+ *
+ * Default template: aggregator-item.html.twig.
+ *
+ * @param array $variables
+ *   An associative array containing:
+ *   - elements: An array of elements to display in view mode.
+ */
+function template_preprocess_aggregator_item(&$variables) {
+  $item = $variables['elements']['#aggregator_item'];
+
+  // Helpful $content variable for templates.
+  foreach (Element::children($variables['elements']) as $key) {
+    $variables['content'][$key] = $variables['elements'][$key];
+  }
+
+  $variables['url'] = check_url($item->getLink());
+  $variables['title'] = SafeMarkup::checkPlain($item->label());
+}
+
+/**
+ * Prepares variables for aggregator feed templates.
+ *
+ * Default template: aggregator-feed.html.twig.
+ *
+ * @param array $variables
+ *   An associative array containing:
+ *   - elements: An array of elements to display in view mode.
+ */
+function template_preprocess_aggregator_feed(&$variables) {
+  $feed = $variables['elements']['#aggregator_feed'];
+
+  // Helpful $content variable for templates.
+  foreach (Element::children($variables['elements']) as $key) {
+    $variables['content'][$key] = $variables['elements'][$key];
+  }
+  $variables['full'] = $variables['elements']['#view_mode'] == 'full';
+  $variables['title'] = SafeMarkup::checkPlain($feed->label());
+}