Examine source code of Page Refreshersf

{
  "manifest_version": 2,
  "name": "Page Refresher",
  "version": "1.0",
  "description": "Automatically refresh the current tab at a set interval.",
  "permissions": [
    "tabs"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d5a0ab1d-85e3-44f1-844e-1a6502e4fd56}"
    }
  }
}