Examine source code of OLI Grid CSS

{
  "description": "Draws a grid on top of a website. Highly Customizable. useful for checking designs that are supposed to follow a grid-based layout. ex:Bootstrap,Foundation,Skeleton,Yaml...",
  "manifest_version": 2,
  "name": "OLI Grid CSS",
  "version": "1.7resigned1",
  "homepage_url": "http://www.kushan.info",
  "icons": {
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "applications": {
    "gecko": {
      "id": "{23fdd71b-8cee-4122-97a3-1d0879ad48bf}"
    }
  },
  "browser_action": {
    "default_icon": "icons/icon-48.png",
    "default_title": "Toggle GRID",
    "default_popup": "popup/config.html"
  }
}