Examine source code of Confie Aqui

{
  "name": "Confie Aqui",
  "description": "No Confie Aqui você encontra cupom de desconto das maiores lojas do Brasil, frete grátis, ofertas, histórico de preço",
  "version": "1.2.3",
  "author": "Confie Aqui <contato@confieaqui.com.br>",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "background.js",
      "js/now-2.3.1.js",
      "now.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "js": [
        "browser-polyfill.js",
        "script.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_start"
    },
    {
      "js": [
        "browser-polyfill.js",
        "contentscript.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_icon": {
      "19": "img/logos/16x16_logo.png",
      "38": "img/logos/48x48_logo.png"
    },
    "default_popup": "popup.html",
    "default_title": "Confie Aqui"
  },
  "web_accessible_resources": [
    "assets/img/*",
    "img/*",
    "js/*"
  ],
  "icons": {
    "16": "img/logos/16x16_logo.png",
    "128": "img/logos/128x128_logo.png"
  },
  "permissions": [
    "storage",
    "unlimitedStorage",
    "webNavigation",
    "notifications",
    "http://*/*",
    "https://*/*",
    "*://*.vigiadepreco.com.br/*"
  ]
}