Server.base.url - relative to user's browser or reverse proxy?

Should the server.base.url setting be relative to the URL in the end user’s browser or relative to the proxy_pass entry in the reverse proxy?

e.g. If my end user accesses my DHIS2 instance at https://my.server.com/ and my reverse proxy connects to Tomcat at http://localhost:8080/ what should be configured for server.base.url in dhis.conf?

I’m guessing it’s relative to the URL in the user’s browser, but wanted to confirm.

Thanks in advance!