Examine source code of Messenger for WhatsApp™

{
  "version": "0.1.2resigned1",
  "manifest_version": 2,
  "short_name": "wamessenger",
  "name": "Messenger for WhatsApp™",
  "background": {
    "page": "lib/chrome/background.html"
  },
  "description": "easy access to WhatsApp from toolbar with badge text notifications.",
  "permissions": [
    "tabs",
    "storage",
    "<all_urls>",
    "webRequest",
    "webRequestBlocking"
  ],
  "browser_action": {
    "default_title": "Messenger for WhatsApp™",
    "default_popup": "data/content_script/popup.html",
    "default_icon": {
      "16": "data/icons/16.png",
      "32": "data/icons/32.png",
      "48": "data/icons/48.png",
      "64": "data/icons/64.png"
    }
  },
  "content_scripts": [
    {
      "all_frames": true,
      "run_at": "document_start",
      "js": [
        "data/content_script/inject.js"
      ],
      "matches": [
        "*://*.web.whatsapp.com/*"
      ]
    }
  ],
  "icons": {
    "16": "data/icons/16.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ef206fda-3358-48d0-99c9-8dd63243fbde}"
    }
  }
}