Examine source code of FTM Uitklappen

{
  "manifest_version": 2,
  "name": "FTM Uitklappen",
  "version": "1.1",
  "description": "Part of text is hidden at webpages matching https://www.ftm.nl/artikelen/*. Hidden text can be found, but is not shown. Press all buttons 'Uitklappen', to show hidden text.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.ftm.nl/artikelen/*"
      ],
      "exclude_matches": [
        "https://www.ftm.nl/artikelen"
      ],
      "js": [
        "uitklappen.js"
      ],
      "run_at": "document_start"
    }
  ]
}