Examine source code of Get Comments

{
  "manifest_version": 2,
  "name": "Get Comments",
  "description": "This extension searches online communites(HN, Reddit) and retrieves comments/discussion pages",
  "version": "1.0.4",
  "browser_action": {
    "default_icon": "img/icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab",
    "*://www.reddit.com/*"
  ],
  "applications": {
    "gecko": {
      "id": "getcomments@example.com"
    }
  }
}