Examine source code of CheckDomain

{
  "manifest_version": 2,
  "name": "CheckDomain",
  "description": "Поиск и регистрация доменов",
  "version": "1.0.6",
  "author": "Timeweb Co., Ltd.",
  "permissions": [
    "storage",
    "https://free-api.timeweb.ru/v1",
    "https://free-api.timeweb.ru/v1/*"
  ],
  "icons": {
    "16": "images/icon-16x16.png",
    "48": "images/icon-48x48.png",
    "128": "images/icon-128x128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "images/icon-48x48.png"
  }
}