Examine source code of Transmission easy client

{
  "manifest_version": 2,
  "browser_action": {
    "default_icon": {
      "16": "assets/icons/icon_16.png",
      "24": "assets/icons/icon_24.png",
      "32": "assets/icons/icon_32.png"
    },
    "default_popup": "index.html#popup",
    "default_title": "__MSG_appName__"
  },
  "background": {
    "scripts": [
      "commons.chunk.js",
      "bg.js"
    ]
  },
  "icons": {
    "16": "assets/icons/icon_16.png",
    "48": "assets/icons/icon_48.png",
    "128": "assets/icons/icon_128.png"
  },
  "permissions": [
    "http://*/*",
    "https://*/*",
    "storage",
    "notifications",
    "tabs",
    "contextMenus"
  ],
  "name": "__MSG_appName__",
  "description": "__MSG_appDesc__",
  "default_locale": "en",
  "version": "2.2.0",
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "48.0"
    }
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  }
}