Examine source code of Give Me Bird

{
  "name": "Give Me Bird",
  "description": "Change twitter icon from X to Bird.",
  "version": "1.0.4",
  "browser_specific_settings": {
    "gecko": {
      "id": "admin@haer0248.me"
    }
  },
  "manifest_version": 3,
  "permissions": [],
  "content_scripts": [
    {
      "matches": [
        "https://twitter.com/*",
        "https://*.twitter.com/*",
        "https://x.com/*",
        "https://*.x.com/*"
      ],
      "js": [
        "main.js"
      ],
      "run_at": "document_start",
      "all_frames": false
    }
  ],
  "web_accessible_resources": [
    {
      "matches": [
        "https://twitter.com/*",
        "https://*.twitter.com/*",
        "https://x.com/*",
        "https://*.x.com/*"
      ],
      "resources": [
        "images/favicon.ico"
      ]
    }
  ],
  "icons": {
    "16": "icons/twitter_x_16.png",
    "32": "icons/twitter_x_32.png",
    "48": "icons/twitter_x_48.png",
    "64": "icons/twitter_x_64.png",
    "128": "icons/twitter_x_128.png"
  }
}