Examine source code of Arcadia CalcX Button

{
  "manifest_version": 3,
  "name": "Arcadia CalcX Button",
  "version": "0.2",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://cp.arcadia-online.org/character/view/?id=*"
      ],
      "js": [
        "script.js"
      ]
    }
  ],
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{3e76d13f-479f-4879-b0a7-6302801b78b2}"
    }
  }
}