Source: dist/css/library_boot.css, line 6965
6.2.5 Grid Filler
This is a styleguide only element to show structure edges.
Example
Grid Area:
<div class="w_auto h_100p c_highlight-n4 font_xbold font_3 br_dotted br_highlight bg_highlight-5 br_1 grid items_center justify_center lh_0 overflow_ellipsis">Grid Area: </div>