Examine source code of DuckDuckGo !bangs

{
  "name": "DuckDuckGo !bangs",
  "description": "Add DuckDuckGo bang buttons to search results and search links in the context menu.",
  "version": "0.6.2resigned1",
  "author": "Simon Engwerda",
  "manifest_version": 2,
  "icons": {
    "16": "images/duckduckgo-16.png",
    "48": "images/duckduckgo-48.png",
    "128": "images/duckduckgo-128.png"
  },
  "default_locale": "en",
  "background": {
    "scripts": [
      "scripts/background.js"
    ]
  },
  "permissions": [
    "tabs",
    "contextMenus",
    "storage"
  ],
  "options_ui": {
    "page": "options.html",
    "chrome_style": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.duckduckgo.com/*"
      ],
      "js": [
        "scripts/contentscript.js"
      ],
      "run_at": "document_end",
      "all_frames": false
    }
  ],
  "omnibox": {
    "keyword": "dd"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{de5abd6c-321f-49cb-b68f-381241ad4e9e}"
    }
  }
}