Examine source code of JustEtf Skat ETF

{
  "manifest_version": 2,
  "name": "JustEtf Skat ETF",
  "version": "2.0.6",
  "description": "Tilføjer skatinfo til justetf.com",
  "short_name": "JustEtfSkat",
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "main.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.justetf.com/*"
      ],
      "js": [
        "contentscript.js"
      ]
    }
  ]
}