Examine source code of Remote Control Extension

{
  "manifest_version": 2,
  "name": "Remote Control Extension",
  "version": "1.2.0",
  "description": "Allows smartphone remote control of YouTube, Netflix, and AniWorld via WebSocket",
  "browser_specific_settings": {
    "gecko": {
      "id": "remote-control-plus@nikita-dev.tools",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "tabs",
    "activeTab",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "all_frames": true,
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ]
}