Examine source code of Tab Refresh

{
  "manifest_version": 2,
  "name": "Tab Refresh",
  "version": "1.1",
  "description": "Refreshes selected tabs at 60 second intervals",
  "icons": {
    "32": "Icons/d32p.png",
    "48": "Icons/d48p.png",
    "64": "Icons/d64p.png",
    "96": "Icons/d96p.png",
    "128": "Icons/d128p.png",
    "192": "Icons/d192p.png",
    "256": "Icons/d256p.png",
    "512": "Icons/d512p.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "16": "Icons/16r.png",
      "32": "Icons/32r.png",
      "48": "Icons/48r.png",
      "64": "Icons/64r.png",
      "96": "Icons/96r.png",
      "128": "Icons/128r.png",
      "192": "Icons/192r.png",
      "256": "Icons/256r.png",
      "512": "Icons/512r.png"
    },
    "default_title": "Tab Refresh"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{96975411-83e6-4b07-8477-481ea508d866}"
    }
  }
}