@hi700. Thanks for posting. I have Joomla 3.9.19 and PHP 7.3.8 on my test server. I have no problems with he extension listing files as it should.
I would love to assist you with your issue. However, I would have to be able to reproduce it in order to diagnose and solve any issue. Have you checked your PHP error logs? It would be helpful to see what error shows up when you try to display the page.
Also, what did you changed on your site prior to this problem you are encountering?
Michael