Examine source code of Download Speed Controller

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "1.0",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "48": "icons/download-48.png"
  },
  "permissions": [
    "downloads",
    "storage",
    "notifications"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/download-48.png",
    "default_popup": "popup.html",
    "default_title": "__MSG_extensionName__"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{123d16af-e18d-42e6-94b4-94c063538cbf}"
    }
  }
}