Examine source code of Profile Number DisplayF

{
  "manifest_version": 2,
  "name": "Profile Number Display",
  "version": "1.0",
  "description": "Отображает номер профиля на иконке расширения",
  "applications": {
    "gecko": {
      "id": "profile-number-display@example.com"
    }
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_title": "Profile Number Display",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  }
}