Examine source code of VK Manager

{
  "version": "2.3.2resigned1",
  "name": "VK Manager",
  "manifest_version": 2,
  "default_locale": "pt_BR",
  "description": "Extensão para o site vk.com",
  "homepage_url": "https://github.com/knoxzin1/vk-manager",
  "browser_action": {
    "default_title": "VK Manager",
    "default_icon": {
      "16": "images/icon_16.png",
      "32": "images/icon_32.png",
      "48": "images/icon_48.png",
      "64": "images/icon_64.png",
      "96": "images/icon_96.png",
      "128": "images/icon_128.png"
    }
  },
  "icons": {
    "16": "images/icon_16.png",
    "32": "images/icon_32.png",
    "48": "images/icon_48.png",
    "64": "images/icon_64.png",
    "96": "images/icon_96.png",
    "128": "images/icon_128.png"
  },
  "options_ui": {
    "chrome_style": true,
    "page": "src/options.html"
  },
  "background": {
    "scripts": [
      "src/options.js",
      "src/api.js",
      "src/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://vk.com/*"
      ],
      "js": [
        "src/options.js",
        "src/contentScript.js"
      ],
      "css": [
        "css/vk.css"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    "src/pageScript.js",
    "lib/marked.js"
  ],
  "permissions": [
    "activeTab",
    "notifications",
    "contextMenus",
    "storage",
    "*://vk.com/*",
    "*://*.vk.com/*",
    "tabs"
  ],
  "applications": {
    "gecko": {
      "id": "extension@vk.manager"
    }
  }
}