Examine source code of NN Stickers

{
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "sargdsra@gmail.com"
    }
  },
  "name": "NN Stickers",
  "version": "0.3",
  "description": "Show NN stickers.",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}