diff -u b/core/lib/Drupal/Core/Theme/ActiveTheme.php b/core/lib/Drupal/Core/Theme/ActiveTheme.php
--- b/core/lib/Drupal/Core/Theme/ActiveTheme.php
+++ b/core/lib/Drupal/Core/Theme/ActiveTheme.php
@@ -202,11 +202,12 @@
    * Otherwise use the default logo.svg file as fallback.
    *
    * @return string
+   *   The logo.
    */
   public function getLogo() {
-    $config = $this->getExtension();
-    if (isset($config->info['logo']) && !empty($config->info['logo'])) {
-      $logo = $config->info['logo'];
+    $extension = $this->getExtension();
+    if (isset($extension->info['logo']) && !empty($extension->info['logo'])) {
+      $logo = $extension->info['logo'];
     }
     else {
       $logo = 'logo.svg';
diff -u b/core/tests/Drupal/KernelTests/Core/Theme/ThemeSettingsTest.php b/core/tests/Drupal/KernelTests/Core/Theme/ThemeSettingsTest.php
--- b/core/tests/Drupal/KernelTests/Core/Theme/ThemeSettingsTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Theme/ThemeSettingsTest.php
@@ -65,42 +65,43 @@
    */
-   public function testLogoConfig() {
-     $theme_handler = $this->container->get('theme_handler');
-     $theme_handler->install(array('test_basetheme'));
-     $theme_handler->setDefault('test_basetheme');
-     $theme = $theme_handler->getTheme('test_basetheme');
-
-     // Test default behaviour.
-     $default = file_url_transform_relative(file_create_url($theme->getPath() . '/logo.svg'));
-     $this->assertIdentical($default, theme_get_setting('logo.url'));
-
-     $config = $this->config('test_basetheme.settings');
-
-     drupal_static_reset('theme_get_setting');
-
-     $values = [
-       'default_logo' => FALSE,
-       'logo_path' => 'public://logo_with_scheme.png',
-     ];
-     theme_settings_convert_to_config($values, $config)->save();
-
-     // Test filename with scheme.
-     $this->assertIdentical(
-       file_url_transform_relative(file_create_url('public://logo_with_scheme.png')),
-       theme_get_setting('logo.url')
-     );
-
-     drupal_static_reset('theme_get_setting');
-
-     $values = [
-       'default_logo' => FALSE,
-       'logo_path' => $theme->getPath() . '/logo_relative_path.gif',
-     ];
-     theme_settings_convert_to_config($values, $config)->save();
+  public function testLogoConfig() {
+    $theme_handler = $this->container->get('theme_handler');
+    $theme_handler->install(array('test_basetheme'));
+    $theme_handler->setDefault('test_basetheme');
+    $theme = $theme_handler->getTheme('test_basetheme');
+
+    // Test default behaviour.
+    $default = file_url_transform_relative(file_create_url($theme->getPath() . '/logo.svg'));
+    $this->assertSame($default, theme_get_setting('logo.url'));
+
+    $config = $this->config('test_basetheme.settings');
+
+    drupal_static_reset('theme_get_setting');
+
+    $values = [
+      'default_logo' => FALSE,
+      'logo_path' => 'public://logo_with_scheme.png',
+    ];
+    theme_settings_convert_to_config($values, $config)->save();
+
+    // Test filename with scheme.
+    $this->assertSame(
+      file_url_transform_relative(file_create_url('public://logo_with_scheme.png')),
+      theme_get_setting('logo.url')
+    );
+
+    drupal_static_reset('theme_get_setting');
 
-     // Test relative path.
-     $this->assertIdentical(
+    $values = [
+      'default_logo' => FALSE,
+      'logo_path' => $theme->getPath() . '/logo_relative_path.gif',
+    ];
+    theme_settings_convert_to_config($values, $config)->save();
+
+    // Test relative path.
+    $this->assertSame(
       file_url_transform_relative(file_create_url($theme->getPath() . '/logo_relative_path.gif')),
       theme_get_setting('logo.url')
-     );
-   }
+    );
+  }
+
 }