manifest.json~

{
  "manifest_version": 2,
  "name": "HTML Tree Generator",
  "description": "While many might think of html as the layout of a page, it is really just a tree of elements. It is the css that handles the layout of these elements on the page. This extension will generate a basic tree of any html page in order to help you visual your site as tree.",
  "version": "1.0",
  "browser_action": {
      "default_popup": "popup.html"
  },
  "icons": {"16": "icon16.png",
           "48": "icon48.png",
          "128": "icon128.png" },
  "permissions": [
    "activeTab"
  ]
}