Examine source code of Hemnet extension

{
  "manifest_version": 2,
  "name": "Hemnet extension",
  "version": "1.1",
  "description": "Calculates the monthly cost for apartments on hemnet. ",
  "icons": {
    "48": "hemnet.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.hemnet.se/bostad/lagenhet-*"
      ],
      "js": [
        "monthly.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{348542ec-276f-4031-9b31-f9a27891f25a}"
    }
  }
}