Examine source code of ServiceWorker Cleaner

{
  "description": "__MSG_description__",
  "manifest_version": 2,
  "name": "Name",
  "version": "1.0",
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png",
    "128": "icons/logo_128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/logo_64.png",
    "default_title": "Delete it!"
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": false
  },
  "permissions": [
    "browsingData",
    "notifications",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d4b2df91-905e-470a-aa1e-0c8c12c7b953}"
    }
  }
}