Examine source code of Wikiborder

{
  "manifest_version": 2,
  "name": "Wikiborder",
  "version": "1.1resigned1",
  "description": "Adds a blue border to all webpages matching wikimedia.org.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.wikimedia.org/*"
      ],
      "js": [
        "wikiborder.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4b41fb16-6469-4a5a-864c-b778b3d83e15}"
    }
  }
}