Examine source code of SoundCloud Keyboard Skip

{
  "manifest_version": 3,
  "name": "SoundCloud Skipper",
  "version": "1.0.2",
  "description": "Skip tracks with the keyboard! Just use CMD/CTRL + RightArrow/LeftArrow to skip forwards/backwards!",
  "content_scripts": [
    {
      "matches": [
        "https://soundcloud.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "icons": {
    "32": "icons/icon32.png",
    "48": "icons/icon48.png"
  },
  "action": {
    "default_icon": {
      "16": "icons/icon16.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{96306855-6037-46c2-b03b-972131e63906}"
    }
  }
}