Examine source code of Kupistul.ua

{
  "name": "Kupistul.ua",
  "description": "Opening website in the new window of your browser. Fast and easy, with one click.",
  "version": "1.1",
  "manifest_version": 2,
  "icons": {
    "48": "icons/icon48x48.png",
    "96": "icons/icon96x96.png"
  },
  "applications": {
    "gecko": {
      "id": "m.alexyan@promodo.com",
      "strict_min_version": "42.0"
    }
  },
  "browser_action": {
    "default_icon": "icons/icon48x48.png",
    "default_title": "Modern app for browser which helps to work with website."
  },
  "background": {
    "scripts": [
      "siteopen.js"
    ]
  }
}