Examine source code of Haze

{
  "manifest_version": 2,
  "name": "Haze",
  "description": "Blur, scratchcard, or hide anything on any website. Peek on hover or click, and toggle it all off in one click.",
  "version": "2.5.2",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "storage",
    "scripting",
    "activeTab",
    "*://www.google.com/search*",
    "*://www.google.co.uk/search*",
    "*://www.google.ca/search*",
    "*://www.google.com.au/search*",
    "*://www.google.de/search*",
    "*://www.google.fr/search*",
    "*://www.google.es/search*",
    "*://www.google.it/search*",
    "*://www.google.nl/search*",
    "*://www.google.co.in/search*",
    "*://www.google.co.jp/search*",
    "*://www.google.com.br/search*",
    "*://www.google.ru/search*",
    "*://www.google.pl/search*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{368c6f74-ca73-440d-b13d-6afc5c4e16a5}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Haze",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "open_in_tab": true,
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.google.ca/search*",
        "*://www.google.co.in/search*",
        "*://www.google.co.jp/search*",
        "*://www.google.co.uk/search*",
        "*://www.google.com.au/search*",
        "*://www.google.com.br/search*",
        "*://www.google.com/search*",
        "*://www.google.de/search*",
        "*://www.google.es/search*",
        "*://www.google.fr/search*",
        "*://www.google.it/search*",
        "*://www.google.nl/search*",
        "*://www.google.pl/search*",
        "*://www.google.ru/search*"
      ],
      "all_frames": false,
      "run_at": "document_start",
      "js": [
        "content-scripts/engine.js"
      ]
    }
  ]
}