Examine source code of Count Tabs

{
  "manifest_version": 2,
  "version": "1.0.2resigned1",
  "name": "__MSG_extName__",
  "description": "__MSG_extDescription__",
  "default_locale": "en",
  "applications": {
    "gecko": {
      "id": "Count-Tabs@sienori"
    }
  },
  "permissions": [
    "tabs"
  ],
  "icons": {
    "16": "images/16.png",
    "32": "images/32.png",
    "64": "images/64.png",
    "128": "images/128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "images/16.png",
      "32": "images/32.png",
      "64": "images/64.png",
      "128": "images/128.png"
    }
  }
}