Examine source code of Search Manager

{
  "version": "0.1.1resigned1",
  "manifest_version": 2,
  "name": "Search Manager",
  "short_name": "searchmanager",
  "permissions": [
    "tabs",
    "*://*/*",
    "storage"
  ],
  "chrome_url_overrides": {
    "newtab": "data/override/index.html"
  },
  "homepage_url": "http://mybrowseraddon.com/search-manager.html",
  "background": {
    "persistent": true,
    "scripts": [
      "background.js"
    ]
  },
  "description": "Search desired keywords with 4 popular search engines.",
  "browser_action": {
    "default_title": "Search Manager",
    "default_icon": {
      "16": "data/icons/16.png",
      "32": "data/icons/32.png",
      "48": "data/icons/48.png",
      "64": "data/icons/64.png"
    }
  },
  "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": "{25d0acc3-4265-41e8-8a1b-ef93c7323723}"
    }
  }
}