Examine source code of Close Right Tabs Button

{
  "name": "Close Right Tabs Button",
  "version": "0.2resigned1",
  "manifest_version": 2,
  "description": "Adds close right tabs button.",
  "icons": {
    "16": "close_right.png",
    "48": "close_right_48.png",
    "128": "close_right_128.png"
  },
  "browser_action": {
    "default_icon": "close_right.png",
    "default_title": "Close Right"
  },
  "background": {
    "scripts": [
      "close_right.js"
    ]
  },
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{0f34a7d3-0dcd-4926-a452-8b4b3fea06f7}"
    }
  }
}