Examine source code of Upside-down web

{
  "manifest_version": 2,
  "name": "Upside-down web",
  "version": "1.1",
  "description": "This plugin rotates all websites by 180deg and gives you a different look at the web! It will try to rotate all websites and will work on most of them. Firefox preferences and settings are not effected. The fun stops as soon as you deactived the plugin.",
  "icons": {
    "32": "icons/upside-32.png",
    "48": "icons/upside-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "upsidedown.js"
      ]
    }
  ]
}