Examine source code of Typing Bot

{
  "manifest_version": 3,
  "name": "Typing Bot",
  "short_name": "TypingBot",
  "description": "Auto Typing Bot for Various Typing Tests.",
  "version": "1.0",
  "author": "JdM",
  "homepage_url": "https://www.rmbi.ch/jdm",
  "browser_specific_settings": {
    "gecko": {
      "id": "typingbot@example.com"
    }
  },
  "action": {
    "default_title": "Typing Bot",
    "default_popup": "popup/index.html"
  },
  "content_scripts": [
    {
      "run_at": "document_end",
      "js": [
        "scripts/10fastfingers.js"
      ],
      "matches": [
        "*://*.10fastfingers.com/*"
      ]
    },
    {
      "run_at": "document_end",
      "js": [
        "scripts/typing-speed.js"
      ],
      "matches": [
        "*://*.typing-speed.net/*"
      ]
    }
  ]
}