Examine source code of Lernabit

{
  "manifest_version": 2,
  "name": "Lernabit",
  "version": "1.1resigned1",
  "description": "Click one button to learn more about the topics on the current page",
  "permissions": [
    "tabs"
  ],
  "content_scripts": [],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icon-48.png",
    "96": "icon-96.png"
  },
  "browser_action": {
    "default_icon": "icon-48.png",
    "default_title": "Lernabit"
  },
  "applications": {
    "gecko": {
      "id": "lernabit@lernabit.com"
    }
  }
}