Examine source code of Google: Кнопка поиска Яндекс, Mail.ru и др.

{
  "manifest_version": 2,
  "name": "__MSG_name__",
  "description": "__MSG_description__",
  "version": "1.0",
  "icons": {
    "128": "icon128.png"
  },
  "applications": {
    "gecko": {
      "id": "yromeqwefvwqfsd@gmail.com"
    }
  },
  "background": {
    "scripts": [
      "set.js"
    ]
  },
  "content_scripts": [
    {
      "js": [
        "back.js"
      ],
      "css": [
        "style.css"
      ],
      "matches": [
        "*://www.google.com/*",
        "*://www.google.ru/*",
        "*://www.google.kz/*",
        "*://www.google.com.ua/*",
        "*://www.google.by/*",
        "*://www.google.uz/*",
        "*://www.google.az/*",
        "*://www.google.kg/*",
        "*://www.google.lt/*",
        "*://www.google.lv/*",
        "*://www.google.md/*",
        "*://www.google.com.br/*",
        "*://www.google.ca/*",
        "*://www.google.de/*",
        "*://www.google.it/*",
        "*://www.google.es/*",
        "*://www.google.fi/*",
        "*://www.google.co.zw/*",
        "*://www.google.co.za/*",
        "*://www.google.com.vn/*",
        "*://www.google.co.ve/*",
        "*://www.google.us/*",
        "*://www.google.com.tw/*",
        "*://www.google.com.tr/*",
        "*://www.google.co.th/*",
        "*://www.google.si/*",
        "*://www.google.se/*",
        "*://www.google.rs/*",
        "*://www.google.ro/*",
        "*://www.google.pl/*",
        "*://www.google.co.nz/*",
        "*://www.google.no/*",
        "*://www.google.mn/*",
        "*://www.google.co.kr/*",
        "*://www.google.co.jp/*",
        "*://www.google.com.jm/*",
        "*://www.google.is/*",
        "*://www.google.hu/*",
        "*://www.google.gr/*",
        "*://www.g.cn/*",
        "*://www.google.cn/*",
        "*://www.google.cl/*",
        "*://www.google.com.af/*"
      ]
    }
  ],
  "browser_action": {},
  "permissions": [
    "storage"
  ],
  "default_locale": "en"
}