Examine source code of FFRef

{
  "manifest_version": 2,
  "name": "FFRef",
  "version": "1.1resigned1",
  "applications": {
    "gecko": {
      "id": "ffref@local.host"
    }
  },
  "permissions": [
    "storage"
  ],
  "description": "Switches to one of multiple amazon ref links on each visit.",
  "icons": {
    "48": "icons/ffref-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.amazon.de/*"
      ],
      "js": [
        "background.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html"
  }
}