Where does the value $ds_content come from in display suite templates? After updating to the newest version of display suite I noticed that in display suite ds-reset.tpl.php the value for $ds_content is now blank.

&lt;?php

/**
 * @file
 * Display Suite reset template.
 */
?&gt;
&lt;?php print $ds_content; ?&gt;
&lt;?php if (!empty($drupal_render_children)): ?&gt;
  &lt;?php print $drupal_render_children ?&gt;
&lt;?php endif; ?&gt;


Where is this value assigned so I can better troubleshoot what the problem is.
Looks like it's set in ds/includes/ds.registry.inc in _ds_ds_layout_info() which implements a hook hook_ds_layout_info