Examine source code of Spiceworks remove margin

{
  "manifest_version": 2,
  "name": "Spiceworks remove margin",
  "version": "1.1resigned1",
  "description": "Removes the side margin on the spiceworks ticket center.",
  "icons": {
    "48": "icons/icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://hjalp.tskoli.is/*"
      ],
      "js": [
        "screenfill.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{062ca5a6-096d-409d-9d7a-e0dd116648d3}"
    }
  }
}