Examine source code of Time on Site

{
  "manifest_version": 2,
  "name": "Time on Site",
  "description": "See where your browsing time goes: per-site timers for today and the last 7 days. Everything is stored locally, no telemetry.",
  "version": "5.1",
  "browser_specific_settings": {
    "gecko": {
      "id": "{a4924ed2-8ac4-49dc-a77f-9a5be818fbd2}",
      "strict_min_version": "101.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "32": "assets/icon-32.png",
    "48": "assets/icon-48.png",
    "64": "assets/icon-64.png",
    "96": "assets/icon-96.png",
    "128": "assets/icon-128.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "background": {
    "scripts": [
      "src/core.js",
      "src/background.js"
    ]
  },
  "browser_action": {
    "default_title": "Time on Site",
    "default_popup": "src/popup.html",
    "default_icon": {
      "32": "assets/icon-32.png",
      "48": "assets/icon-48.png",
      "64": "assets/icon-64.png",
      "96": "assets/icon-96.png",
      "128": "assets/icon-128.png"
    }
  }
}