Examine source code of Page Refresherr

{
  "manifest_version": 2,
  "name": "Page Refresher",
  "version": "1.0",
  "description": "Automatically refresh the current tab at set intervals.",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "48": "icon.png"
    },
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6b604374-309a-4c74-9160-b10c5f636ae5}"
    }
  }
}