Examine source code of DLyrics

{
  "manifest_version": 2,
  "name": "DLyrics",
  "version": "0.3",
  "description": "Extension that will allow you to search for songs lyrics. The extension will search automatically by video title that you are watching on youtube to speed up the process.",
  "icons": {
    "98": "icons/logo.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icons/logo.png",
    "default_title": "DLyrics Beta.",
    "default_popup": "popup/menu.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "dlyrics.js"
      ]
    }
  ]
}