Examine source code of StandUp!

{
  "manifest_version": 2,
  "name": "StandUp!",
  "version": "1.0.4resigned1",
  "description": "Notifies the user after a specified interval to get up and stretch a bit.",
  "homepage_url": "https://github.com/Azlond/StandUp",
  "icons": {
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "alarms",
    "tabs",
    "notifications",
    "<all_urls>",
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{065b3d43-bbfe-47de-a835-a212ec7277dd}"
    }
  }
}