As mentioned here: 49c9b05
This change probably breaks compatibility with any existing project that defines their own admin/base_site.html template, which I believe is the recommended way for people to extend the Django admin template without duplicating base.html.
Changing the order of INSTALLED_APPS won't help. It's either our base_site.html or yours.
Is there another way you can implement django-flat-theme without adding the flat-theme class directly to the body tag in this template? Maybe django-flat-theme can just live without it? Or you could duplicate the base.html template. That would be ideal for people wanting to use django-flat-theme with their own projects, as it would remain more of a drop in replacement.