Examine source code of Wallpaper for sites

{
  "manifest_version": 2,
  "default_locale": "ru",
  "name": "__MSG_name__",
  "description": "__MSG_description__",
  "version": "1.46.5",
  "permissions": [
    "storage",
    "tabs",
    "cookies",
    "activeTab",
    "<all_urls>"
  ],
  "background": {
    "page": "background.html"
  },
  "applications": {
    "gecko": {
      "id": "sitepaper@iliz.net",
      "strict_min_version": "48.0"
    }
  },
  "page_action": {
    "default_icon": "icon48.png",
    "default_title": "__MSG_name__",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icon16.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "css": [
        "site-all.css"
      ],
      "js": [
        "common.js",
        "site-google.com.js"
      ],
      "matches": [
        "*://www.google.com/*",
        "*://www.google.com.ua/*",
        "*://www.google.by/*",
        "*://www.google.ru/*",
        "*://www.google.pl/*",
        "*://www.google.no/*",
        "*://www.google.se/*",
        "*://www.google.de/*",
        "*://www.google.fr/*"
      ],
      "run_at": "document_start"
    },
    {
      "css": [
        "site-all.css"
      ],
      "js": [
        "common.js",
        "site-vk.com.js"
      ],
      "matches": [
        "*://vk.com/*"
      ],
      "run_at": "document_start"
    },
    {
      "css": [
        "site-all.css"
      ],
      "js": [
        "common.js",
        "site-mamba.ru.js"
      ],
      "run_at": "document_start",
      "matches": [
        "*://www.mamba.ru/*",
        "*://wamba.com/*",
        "*://love.mail.ru/*",
        "*://www.love.mail.ru/*",
        "*://love.rambler.ru/*",
        "*://www.love.rambler.ru/*"
      ]
    },
    {
      "css": [
        "site-all.css"
      ],
      "js": [
        "common.js",
        "site-loveplanet.ru.js"
      ],
      "run_at": "document_start",
      "matches": [
        "*://loveplanet.ru/*",
        "*://www.loveplanet.ru/*"
      ]
    },
    {
      "css": [
        "site-all.css"
      ],
      "js": [
        "common.js",
        "site-rutracker.org.js"
      ],
      "run_at": "document_start",
      "matches": [
        "*://rutracker.org/*"
      ]
    },
    {
      "css": [
        "site-all.css"
      ],
      "js": [
        "common.js",
        "site-pikabu.ru.js"
      ],
      "run_at": "document_start",
      "matches": [
        "*://pikabu.ru/*"
      ]
    },
    {
      "css": [
        "site-all.css"
      ],
      "js": [
        "common.js",
        "site-youtube.com.js"
      ],
      "run_at": "document_start",
      "matches": [
        "*://*.youtube.com/*"
      ]
    }
  ],
  "web_accessible_resources": [
    "icon16.png"
  ]
}