Examine source code of Youtube Hide Opinion

{
  "manifest_version": 2,
  "name": "Youtube Hide Opinion",
  "version": "1.4",
  "description": "Hides number of likes and dislikes from Youtube",
  "icons": {
    "48": "icons/youtuber.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "hide-opinion.js"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "hideopinion@exts.krydos.com"
    }
  }
}