Nextcloud Request URL

NextCloud version: 15.0.2
Apache or nginx version (eg, Apache 2.4.25) : Apache
PHP version:

The issue you are facing:
How do I determine the Request URL when using the File access control feature? Specifically, how do I choose a specific URL for a file/folder?

The request-URL is normally in your webserver logs. There is a point in the documentation, not sure about this myself:

It says the URL the file is served from. So you can allow/disallow direct webdav access or just via interface or even a specific app? If you get more information, it would be great to extend the documentation a bit.

Basically i was using " " as request URL in File access control request URL option but its not working for any file/folder.