The Box template uses few page suffixes which can be configured under the template settings in the Features tab:
The most important page suffixes are following:
- frontpage-grid - used for generating proper spacing on the frontpage layout,
- nav-transparent - used for generating transparent menu bar (added automatically for all K2 and com_content item pages with set featured image),
- error-page - used on the custom error page - added automatically.
By Super User