Examine source code of Efatura Amigo

{
  "name": "Efatura Amigo",
  "description": "Ferramenta de ajuda na pré-seleção de categorias nas faturas do Portal EFatura",
  "version": "1.2.0",
  "manifest_version": 3,
  "action": {
    "default_popup": "index.html",
    "default_title": "Open the popup"
  },
  "icons": {
    "16": "logo192.png",
    "48": "logo192.png",
    "128": "logo192.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5884c18a-64bc-4d09-a7f0-1fa61a447d88}"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://faturas.portaldasfinancas.gov.pt/resolverListaPendenciasAdquirenteForm.action",
        "https://faturas.portaldasfinancas.gov.pt/resolverListaPendenciasAdquirente.action"
      ],
      "js": [
        "./static/js/content.js"
      ]
    }
  ]
}