Detect if Safari Extension is Installed

Question

Is there a way through JavaScript to detect if a Safari Extension is already installed? https://extensions.apple.com has some way of doing it because they update the install

Answer 1

To detect your extension server-side, the easiest way is to inject a session cookie in your domain with a content script.

In Chrome and Firefox, you could inject an HTTP Header, but the API in Safari does not allow it.

The problem with cookies: if your user uninstall the extension, you will notice only when his session ends (closing browser).