Examine source code of DOM highlighter

{
  "name": "Dom elements highlighter",
  "description": "is a web extension that allows the user to outline all the elements of the web view (it helps to show the designer or the web developer to explore and see how things are desgined and builed.) ",
  "version": "1.0",
  "manifest_version": 2,
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icons/favicon-16x16.png",
    "32": "icons/favicon-32x32.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f7395c66-dafa-42d3-b506-c1774d15881b}"
    }
  }
}