MDL-14637 "allow activity modules to add sub menus of settings pages to admin menu" and MDL-14565 "allow quiz reports to add configuration settings to the admin tree" added a mechanism to admin/settings/plugins.php to allow modules to include a file settingstree.php instead of settings.php which will allow for more flexibility of what a module can add to the admin settings menu.
Merged from 1.9
Added a comment to the if branch that includes config.html that this branch needs to be deleted as soon as quiz/config.html has been migrated to settingstree.php which is MDL-7010