Examine source code of Dom Element Display

{
  "manifest_version": 2,
  "name": "Dom Element Display",
  "version": "0.1",
  "description": "Display the html representation of the wanted element",
  "homepage_url": "https://github.com/thibsc/myFirefoxAddons",
  "icons": {
    "48": "assets/icons/programming.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "src/displayer.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "assets/icons/programming.png",
    "default_title": "Dom Element Display"
  }
}