Examine source code of amrating

{
  "manifest_version": 3,
  "name": "amrating",
  "version": "1.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "amratings@trickydev.io"
    }
  },
  "description": "Adds back the rating count next to each item in Amazon search results.",
  "content_scripts": [
    {
      "matches": [
        "*://*.amazon.com/*"
      ],
      "js": [
        "amrating.js"
      ]
    }
  ],
  "host_permissions": [
    "https://*.amazon.com/*"
  ],
  "permissions": [
    "tabs",
    "activeTab"
  ]
}