Particle features "apps" which simply consume the design system in source/ and then present it according to their needs. 
Adding or Removing Apps
Particle makes adding or removing apps a snap! By default Particle has a Pattern Lab installation, a Drupal theme, and a Grav theme included. But these can be added to, removed, or changed easily. If you'd like to make changes, see these pieces:
module.exportsinconfig.js- Path imports in 
gulpfile.js - If the app is twig-based, 
twigNamespacestask ingulpfile.js devandbuildscripts inpackage.json- Add or delete App folder under 
/apps - Special: to remove Grav, delete 
particle.yaml