Examine source code of fcku.it

{
  "description": "A firefox addon that let's you post a link of the current page to fcku.it",
  "manifest_version": 2,
  "name": "fcku.it",
  "version": "1.1.3",
  "homepage_url": "https://fcku.it/",
  "applications": {
    "gecko": {
      "id": "{70e52a0a-e310-4cf3-9246-6849be580974}"
    }
  },
  "icons": {
    "48": "resources/icon-48.png"
  },
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "fcku.it",
    "default_icon": "resources/icon-32.png",
    "theme_icons": [
      {
        "light": "resources/icon-32-light.png",
        "dark": "resources/icon-32.png",
        "size": 32
      }
    ]
  }
}