Examine source code of Tab Time Tracker

{
  "manifest_version": 2,
  "name": "Tab Time Tracker",
  "version": "1.0.0",
  "description": "Track how much time you spend on each browser tab. Data is stored locally only.",
  "permissions": [
    "tabs",
    "storage"
  ],
  "browser_action": {
    "default_title": "Tab Time Tracker",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icon-48.png",
    "96": "icon-96.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tab-time-tracker-amo-safe@example.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}