Examine source code of Monkey Type Practice Words

{
  "manifest_version": 3,
  "name": "Monkey Type Practice Words",
  "version": "1.0.2",
  "description": "Open and launch practice words menu with spacebar after tests, with a 400ms delay to prevent accidental triggers",
  "browser_specific_settings": {
    "gecko": {
      "id": "{9034fc6a-cd0b-4389-a15c-a80de108dbf5}"
    }
  },
  "icons": {
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "action": {
    "default_icon": {
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "64": "icons/icon-64.png",
      "96": "icons/icon-96.png",
      "128": "icons/icon-128.png"
    },
    "default_title": "Monkey Type Practice Words"
  },
  "content_scripts": [
    {
      "matches": [
        "https://monkeytype.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "activeTab"
  ]
}