Examine source code of Lunapic Image Edit

{
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "description": "Easy way to edit images on Lunapic.com. Right click an image and open edit session on Lunapic.com.",
  "icons": {
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "manifest_version": 2,
  "name": "Lunapic Right Click Edit",
  "page_action": {
    "default_icon": "icon.png",
    "default_title": "Lunapic Right Click"
  },
  "permissions": [
    "contextMenus"
  ],
  "update_url": "http://clients2.google.com/service/update2/crx",
  "version": "1.1"
}