Examine source code of Chordoke Chords + Karaoke

{
  "background": {
    "scripts": [
      "/assets/js/chordoke.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "128": "assets/images/default.png"
    }
  },
  "description": "Chords + karaoke, find chords and karaokes...",
  "icons": {
    "128": "assets/images/default.png"
  },
  "manifest_version": 2,
  "minimum_chrome_version": "40",
  "name": "Chordoke",
  "version": "1.0"
}