Examine source code of SoundCloudExtra

{
  "name": "SoundCloudExtra",
  "version": "1.7.0",
  "description": "Download tracks, manage cache, and more",
  "manifest_version": 2,
  "icons": {
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "permissions": [
    "storage",
    "tabs",
    "browsingData",
    "*://*.soundcloud.com/*",
    "*://*.sndcdn.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://soundcloud.com/*"
      ],
      "all_frames": true,
      "js": [
        "browser-id3-writer.js",
        "content.js",
        "settings.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a17cb4b2-86d7-4c51-8c61-f2ff2d21420b}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}