Examine source code of Machine View

{
  "manifest_version": 2,
  "name": "Machine View",
  "version": "1.2",
  "description": "Looks under the skin of a web page to present your metadata, title text, heading text, link text and targets, and your image alt text",
  "icons": {
    "48": "icons/machine-view-48.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "purify.min.js",
        "machine-view.js"
      ],
      "css": [
        "mv.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "action.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/machine-view-48.png",
    "default_title": "Machine view"
  }
}