Examine source code of steamID simple copy

{
  "manifest_version": 2,
  "name": "steamID simple copy",
  "description": "Выводим steamID на странице, в удобном формате с кнопкой для копирования",
  "version": "1.1",
  "author": "angrypy",
  "browser_action": {
    "default_title": "Вывод steamID",
    "default_icon": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://steamcommunity.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "steamId.css"
      ]
    }
  ],
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{58dc09de-ae2f-440d-ac79-9452eb1d4aa8}"
    }
  }
}