Examine source code of MonkeyType X MelodyType

{
  "manifest_version": 3,
  "name": "MonkeyType X MelodyType",
  "version": "0.6",
  "description": "Embed Melodytype.com into Monkeytype.com and have fun typing lyrics",
  "icons": {
    "16": "16.png",
    "48": "48.png",
    "128": "128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.monkeytype.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ]
    },
    {
      "matches": [
        "*://*.melodytype.com/*"
      ],
      "js": [
        "iframe-content.js"
      ],
      "all_frames": true
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "styles.css",
        "iframe-styles.css"
      ],
      "matches": [
        "*://*.monkeytype.com/*",
        "*://*.melodytype.com/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "monkeytype-x-melodytype@example.com",
      "strict_min_version": "135.0"
    }
  }
}