Examine source code of Tab Auto Refresha

{
  "manifest_version": 2,
  "name": "Tab Auto Refresh",
  "version": "1.0",
  "description": "Automatically refreshes the current tab at a set interval.",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{eeb8c78d-f3af-41b2-b9ae-6a6b75dce8bf}"
    }
  }
}