Developer credits
Git commits in Moodle 2.6.x by Amy Groshek
commit dc3337b273b4785b670d75174d2570f3e8c0b22f Author: Amy Groshek <amygroshek@gmail.com> Date: Fri, 25 Jan 2013 06:15:12 +0800 Tag: v2.6.0-beta MDL-37674 - modify html_attributes() to add .no-header class when header will not be rendered