diff -u b/sites/default/default.settings.php b/sites/default/default.settings.php
--- b/sites/default/default.settings.php
+++ b/sites/default/default.settings.php
@@ -315,7 +315,7 @@
  * setting and set it to TRUE to allow an insecure fallback to HTTP. Note that
  * doing so will open your site up to a potential man-in-the-middle attack. You
  * should instead attempt to resolve the issues before enabling this option.
- * @see https://drupal.org/link/to/docs/about/certfiles (@todo)
+ * @see https://www.drupal.org/docs/system-requirements/php-requirements#openssl
  * @see https://en.wikipedia.org/wiki/Man-in-the-middle_attack
  * @see \Drupal\update\UpdateFetcher
  */