Examine source code of Fitness Reminder

{
  "manifest_version": 2,
  "name": "Fitness Reminder",
  "version": "1.0",
  "description": "Reminds you to take fitness breaks at regular intervals.",
  "icons": {
    "48": "icons/fitness-icon-48.png"
  },
  "permissions": [
    "notifications",
    "alarms"
  ],
  "browser_action": {
    "default_icon": "icons/fitness-icon-48.png",
    "default_popup": "fitness-popup.html",
    "default_title": "Fitness Reminder"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d277f778-8d45-414b-95da-02c5e1050a5d}"
    }
  }
}