Examine source code of Mastodon Chirper

{
  "manifest_version": 3,
  "name": "Mastodon Chirper",
  "version": "1.4.2",
  "description": "Add Mastodon posts to your twitter.com home timeline feed",
  "icons": {
    "16": "images/logo-green-16.png",
    "32": "images/logo-green-32.png",
    "48": "images/logo-green-48.png",
    "128": "images/logo-green-128.png"
  },
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEApzLPt5QtL1XkEWTwuzOSXzjdXz1ehYlKKBRbW6ps8Fp1aszsEJyLvSMwiFxSwvyTSDLrLOkurkkBj9e1UPIgMUSOWYjO4V+s0/vCsd3JJGlZJ/sfwxKM9EpxyrpaW0nDZONOwx/pfKxOFvvyuqOxSUa4y3zM5EZrdVnUDeyq0WzrBFvUaPJi9XP4y0IpfegKc/rx4uFDOAncvSqTVIoyCYacGvZ7Tz06bOar9Jcv5iiAXtBZG21yecQXl+bWihAjKY1CJuDqlcDr6CGZnofGjngI0DsticY6yg1RIBkGtFuOjxBEDKdG1njHGTAot+xMkFnH3jy0j4ATnEliLDXIGwIDAQAB",
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "*://twitter.com/*"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "xhr_capture.js",
        "rewriter.js"
      ],
      "matches": [
        "*://twitter.com/*"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "identity",
    "storage",
    "unlimitedStorage"
  ],
  "host_permissions": [
    "*://twitter.com/*"
  ],
  "optional_permissions": [
    "*://*/*"
  ],
  "action": {
    "default_popup": "chirper.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "chirper@picheta.me",
      "strict_min_version": "109.0"
    }
  }
}