Examine source code of Domain Cookie Reaper

{
  "manifest_version": 2,
  "name": "Domain Cookie Reaper",
  "version": "1.2.0",
  "description": "Deletes cookies for configured domain(s) when the last tab leaves that domain (per container), with a short delay.",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "tabs",
    "cookies",
    "storage",
    "notifications",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "domain-cookie-reaper@furcom.org",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}