Examine source code of MultiRoblox

{
  "manifest_version": 2,
  "name": "MultiRoblox",
  "version": "1.1.6",
  "description": "MultiRoblox will help you change your account easily!",
  "icons": {
    "128": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "cookies",
    "storage",
    "*://*.roblox.com/*"
  ],
  "applications": {
    "gecko": {
      "id": "{7d52a570-d57f-42d8-8c16-be98be2eeab8}",
      "strict_min_version": "42.0"
    }
  }
}