Examine source code of Work Timer

{
  "manifest_version": 2,
  "name": "Work Timer",
  "version": "1.1",
  "description": "A simple work timer tool - record tasks and duration, export to CSV.",
  "icons": {
    "48": "icons/timer-48.png",
    "96": "icons/timer-96.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "work-timer@shanjia",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "browser_action": {
    "default_icon": "icons/timer-48.png",
    "default_title": "Work Timer",
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage"
  ]
}