Examine source code of yt-focus

{
  "manifest_version": 2,
  "name": "yt-focus",
  "version": "1.1",
  "description": "Fights binge watch by removing recommended videos and other distracting elements.",
  "icons": {
    "48": "icons/yt-focus-48.png",
    "96": "icons/yt-focus-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "yt-focus.js"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "yt-focus@anpeshne"
    }
  }
}