Examine source code of Typing Statistics

{
  "browser_specific_settings": {
    "gecko": {
      "id": "typingstatistics.itsmarzzzzzz@protonmail.com"
    }
  },
  "name": "Typing Statistics",
  "version": "2.3.1",
  "manifest_version": 3,
  "description": "Typing Statistics: Tracks WPM and other Statistics",
  "author": "Marsss' Dev Team",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "/scripts/contentScript.js"
      ]
    }
  ],
  "action": {
    "default_popup": "/popup/popup.html"
  },
  "permissions": [
    "scripting",
    "activeTab",
    "storage",
    "tabs"
  ],
  "icons": {
    "16": "assets/icon-16.png",
    "32": "assets/icon-32.png",
    "48": "assets/icon-64.png",
    "128": "assets/icon-128.png"
  }
}