Examine source code of Timer for Tabs

{
  "manifest_version": 2,
  "name": "Timer for Tabs",
  "version": "1.2",
  "description": "Tracker for time spent on websites",
  "icons": {
    "96": "icons/icon96.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "alarms"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/96.png",
    "default_popup": "popup/popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{aeebcb90-908a-42f5-a824-cd5bc7c48011}",
      "strict_min_version": "95.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}