Examine source code of xpathsearch

{
  "manifest_version": 2,
  "name": "xpathsearch",
  "version": "1.0",
  "permissions": [
    "<all_urls>",
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "xpathsearch.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "xpfinder.png"
  },
  "browser_action": {}
}