Examine source code of Mobile YouTube Fix

{
  "manifest_version": 2,
  "name": "Mobile YouTube Fix",
  "description": "Adds features from desktop version to mobile version of YouTube.",
  "version": "0.3",
  "applications": {
    "gecko": {
      "id": "mobile-youtube-fix@ris58h"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://m.youtube.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}