Examine source code of SoundCloud Discord RPC

{
  "manifest_version": 3,
  "name": "SoundCloud Discord RPC",
  "version": "1.0",
  "permissions": [
    "activeTab"
  ],
  "host_permissions": [
    "http://127.0.0.1:8765/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "soundcloud-rpc@reimo",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://soundcloud.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}