Examine source code of GitZip

{
  "manifest_version": 2,
  "name": "GitZip",
  "description": "It can make the sub-directories and files of github repository as zip and download it",
  "version": "1.0.2",
  "page_action": {
    "default_icon": "images/icon-128px.png",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html"
  },
  "background": {
    "page": "background.html"
  },
  "permissions": [
    "storage",
    "activeTab",
    "contextMenus",
    "theme",
    "*://github.com/*",
    "https://api.github.com/repos/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://github.com/*"
      ],
      "js": [
        "js/content/jszip.min.js",
        "js/content/FileSaver.min.js",
        "js/content/main.js"
      ],
      "css": [
        "css/main.css"
      ]
    },
    {
      "matches": [
        "*://kinolien.github.io/gitzip/*"
      ],
      "js": [
        "js/content/keysync.js"
      ]
    },
    {
      "matches": [
        "*://gitzip.org/gettoken/success"
      ],
      "js": [
        "js/content/autosave.js"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "gitzip-firefox-addons@gitzip.org"
    }
  }
}