Drixel 5 is the HTML 5 version of the Drixel theme which is based on the GPL licensed Pixel Wordpress theme.
Original Wordpress Theme Link
http://samk.ca/freebies/pixel/
The Drupal version (Drixel) includes additional styling for Drupal.
Drixel 5 uses the new markup tags available in HTML 5 such as <section>,<article>,<figure>, etc...
