I think the FSF would consider this a distribution and require the backend to be released under the GPL.<p><a href="https:&#x2F;&#x2F;www.drupal.org&#x2F;node&#x2F;173294" rel="nofollow">https:&#x2F;&#x2F;www.drupal.org&#x2F;node&#x2F;173294</a><p>Er, actually it may be more complicated than that. You&#x27;ll have to read the discussion.