diff --git a/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
index 662239a..3238ce6 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
@@ -164,8 +164,10 @@ public function scan($type, $include_tests = NULL) {
       $searchdirs[static::ORIGIN_PARENT_SITE] = $parent_site;
     }
 
-    // Find the site-specific directory to search. Kernel service is not always
-    // available at this point, but is preferred, when available.
+    // Find the site-specific directory to search. Since we are using this
+    // method to discover extensions including profiles, we might be doing this
+    // at install time. Therefore Kernel service is not always available, but is
+    // preferred.
     if (\Drupal::hasService('kernel')) {
       $searchdirs[static::ORIGIN_SITE] = \Drupal::service('site.path');
     }