Examine source code of Tube-U Boost

{
  "manifest_version": 3,
  "name": "Tube-U Boost",
  "version": "1.3.0",
  "description": "Get 3x more credits on Tube-U. Boost stretches every credit pack 3x further.",
  "browser_specific_settings": {
    "gecko": {
      "id": "boost@tube-u.com",
      "strict_min_version": "128.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "declarativeNetRequest",
    "contextMenus"
  ],
  "declarative_net_request": {
    "rule_resources": [
      {
        "id": "headers",
        "enabled": true,
        "path": "rules.json"
      }
    ]
  },
  "host_permissions": [
    "https://www.youtube.com/*",
    "https://m.youtube.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://tube-u.com/*",
        "https://*.tube-u.com/*",
        "https://*.onrender.com/*",
        "http://localhost/*",
        "http://127.0.0.1/*"
      ],
      "js": [
        "content-bridge.js"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "icons": {
    "48": "icon48.png",
    "128": "icon128.png"
  }
}