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
@@ -441,15 +441,10 @@
 # $settings['cache_ttl_4xx'] = 3600;
 
 /**
- * Expiration of cache_form entries.
+ * Expiration of cached forms.
  *
  * Drupal's Form API stores details of forms in a cache and these entries are
  * kept for at least 6 hours by default. Expired entries are cleared by cron.
- * Busy sites can encounter problems with the cache_form table becoming very
- * large. It's possible to mitigate this by setting a shorter expiration for
- * cached forms. In some cases it may be desirable to set a longer cache
- * expiration, for example to prolong cache_form entries for Ajax forms in
- * cached HTML.
  *
  * @see \Drupal\Core\Form\FormCache::setCache()
  */