Examine source code of Refresher

{
  "manifest_version": 2,
  "name": "Refresher",
  "description": "Refresh a web page on a chosen interval.",
  "version": "2.0.1",
  "icons": {
    "64": "icons/timer.svg"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "browser_action": {
    "default_icon": {
      "64": "icons/timer.svg"
    },
    "default_popup": "browserAction/index.html",
    "default_title": "Refresher",
    "browser_style": true
  },
  "options_ui": {
    "page": "options/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6097c127-16ea-4aa7-8a33-2694e547664b}"
    }
  }
}