Examine source code of YouTube Focus Mode

{
  "manifest_version": 2,
  "name": "YouTube Focus Mode",
  "version": "1.0.0",
  "description": "Remove all distractions from YouTube. Watch without noise.",
  "author": "Azim",
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon48.png"
    },
    "default_title": "YouTube Focus Mode"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "permissions": [
    "storage",
    "*://*.youtube.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "@youtube-focus-mode",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}