UPDATE: This bug on drupal.org has been fixed. I'll keep this article published, but it will no longer be listed on the front page.
Drupal.org is now (as of Halloween 2013) on D7. This is good news with improved features, especially in the issue queues. However, something happened with the upgrade that broke my drush make. There's something different in the project information on drupal.org. (See: https://github.com/drush-ops/drush/issues/234 if you'd like more info.)