Examine source code of SVJ+ Importer

{
  "name": "SVJ+ Importer",
  "version": "1.0.1",
  "description": "Import dat z Katastru nemovitostí pro https://svj.plus",
  "manifest_version": 2,
  "permissions": [
    "tabs",
    "https://nahlizenidokn.cuzk.cz/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "page_action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  }
}