Drupal Lightning
November 2, 2021: So long and thanks for all the fish!
Acquia ended support for the Lightning distribution on November 2, 2021, simultaneously with Drupal 8. Lightning 3, 4, and 5 no longer receive any security updates or bug fixes. It is possible to safely uninstall Lightning from your site; please see the official announcement, FAQ for site owners, and developer instructions for more information.